Sonic Generations is a main series title in the Sonic franchise, released in 2011 for the PlayStation 3, Xbox 360, the PC (via Steam), and the Nintendo 3DS to commemorate Sonic's 20th anniversary. The HD version, subtitled "White Time-Space" in Japan, is the main version of the game, while the 3DS version, subtitled "Blue Adventure" in Japan, is a Reformulated Game with some aspects unique to it.

The story is that Modern Sonic and his friends are celebrating his birthday when the "Time Eater", a mysterious new enemy, crashes the party and sends them back to the past, where Sonic meets his younger self, Classic Sonic. They both discover that the world is losing its color, their friends have been petrified, and disruptions in the timeline have caused places from their past to be frozen in time. Both Modern and Classic must team up to stop this mysterious enemy, rescue their friends, restore color to the world, and fix the timeline. Along the way, they fight familiar foes, including their rivals Metal Sonic, Shadow, and Silver.

Classic Sonic's gameplay takes heavily from the Sega Genesis installments of the series: 2½D gameplay with a focus on momentum-based platforming and maintaining a top speed by taking the optimal route through the stages. Modern Sonic, meanwhile, varies depending on the version: the HD version plays like Sonic Unleashed's daytime stages and the Wii version of Sonic Colors, with Sonic boosting through stages that switch between 3D and side-scrolling segments, while the 3DS version is entirely side-scrolling, more akin to the Sonic Rush series and the DS version of Sonic Colors.

Both HD console versions and the 3DS version support stereoscopic 3D. The HD version requires a 3D-compatible monitor to play in 3D, while the 3DS version natively outputs in autostereoscopic 3D, though it's optional in both cases.

The two Sonics' journey takes them through three eras: Classic, Dreamcast, and Modern. The HD and 3DS versions have different levels and bosses: the only shared aspects are the famous Green Hill Zone from Sonic 1, the rival battles, and the Final Boss.

The stages and bosses are:

The PC version of Sonic Generations is well-known for being one of the most enduringly popular games in the series, with strong sales and an active modding community over a decade after its debut. In 2017, two similar games were released in the Sonic series. While not direct follow-ups, both borrow aspects from Generations and celebrate the series' 25th anniversary — Sonic Mania is a retraux side-scroller that focuses on revisiting classic levels, while Sonic Forces features Modern and Classic Sonic side-by-side again, along with a brand new gameplay style in the form of the Avatar.

I guess we have to trope like there's no tomorrow, or there won't be a tomorrow!

• 2½D: Used to varying degrees. Classic Sonic's gameplay focus remains strictly on a 2D plane in a 3D environment (and occasional 3D set pieces), while Modern Sonic's gameplay uses the same formula used for Sonic Colors and Sonic Unleashed's Daytime stages. The 3DS version is entirely in 2.5D, but with the Sonic Rush feel for Modern and a platforming-focused feel of the Genesis games for Classic.
• A Birthday, Not a Break: The Time Eater crashes Sonic's birthday party in the game's opening.
• Action Commands: By jumping off of certain ramps or through rainbow rings, Modern Sonic can perform tricks when you press in different directions. These are also used to dodge the orca's attacks in Modern Sonic's portion of Emerald Coast in the 3DS version.
• Advancing Wall of Doom:
  • The G.U.N. Truck chases both Sonics in City Escape. Modern Sonic’s version is upgraded with giant, retractable buzz saws and jet boosters to be able to keep up with the Sonic Boost.
  • The orca chase sequence from Emerald Coast returns in the 3DS version. Classic Sonic requires pure speed to get away from it, but Modern Sonic has to dodge its bites as well after it chases him into the air.
• After the End: Crisis City in the HD version takes place in an alternate reality where the world has been devastated by an insane Sun god.
• Already Met Everyone: If you have him turned on before the game starts, Omochao meets Classic Sonic in Green Hill Zone within the prologue, implying he already knew Sonic for a while before you first get to experience him trying to help Sonic and his friends in Sonic Adventure 2.
• Alternate Continuity: Sonic's friends are absent from the 3DS version, due to Sonic arriving at the party before it began and nobody but Tails was present since he was still setting up. Then the Time Eater just attacks the two. Also, the 3DS version has Classic Sonic learn how to use the Homing Attack, and at the end, how to Boost.
• Alternate Timeline: If Sonic Forces is to be believed, the two Eggmen's attempts to change the timeline resulted in Classic Sonic's world diverging into a new timeline leading into Sonic Mania.
• And I Must Scream:
  • Sonic's friends are still self-aware while petrified. In such state, they feel as if they were floating without a body in a black limbo, which Tails states is a feeling that will give him nightmares for weeks.
  • In the epilogue, two different time-period versions of Eggman are stuck in a state of absolute nothing for what appears to be a long, long time. They return back to their respective worlds the next time we see them though.
• Amusement Park: Tropical Resort on the 3DS takes place on Eggman's Interstellar Amusement Park of Doom. Planet Wisp would be this too, but Sonic crashes it while it's still under construction.
• Anti-Frustration Features:
  • In order to successfully attack Perfect Chaos, the Boost move must be used. Normally this is impossible when the boost meter is empty, but in this case it's possible no matter what.
  • In the HD Shadow and Silver rival fights, the stages is dotted with destroyable debris and, in Shadow's stage, trick ramps so that you can still recharge your boost meter even after exhausting the stock of rings in the stage.
• Arbitrary Skepticism: Subverted. When Tails remarks upon how strange their present situation is, Sonic points out that it's no stranger than rescuing genies in magic books or freeing aliens from an interstellar amusement park.
• Art Evolution:
  • Perfect Chaos has undergone a considerable redesign, looking much different than his original form. Compare his Sonic Adventure design◊ to the Sonic Generations design.◊ Apparently, this was how he was originally intended to look; however, due to technological limitations, they were unable to do it, resulting in the Chaos from Sonic Adventure. (The version seen in Sonic Generations does resemble the Perfect Chaos seen in the intro cinematic for Sonic Adventure and its DX counterparts.)
  • Classic Metal Sonic seems to have undergone a minor one by contrast, since his proportions and height are slightly different than his original sprites or artwork for the classic games (specifically, he's much rounder and shorter). This was probably done just to keep him proportionally identical to Classic Sonic, and better distinguish him from Modern Metal Sonic.
• Ascended Meme:
  • A subtle one: Shadow has that DAMN fourth Chaos Emerald as a reward for his rival fight in the HD version. (His rival fight just unlocks the boss in the 3DS version, as Chaos Emeralds are gained through Special Stages in it.)
  • The description for the HD version's "Look Both Ways" achievement counts as well: "Reach the goal in CRISIS CITY Act 2 without being hit by tornado-carried cars or rocks."
• Attack of the Town Festival: Spagonia appears to be in the middle of a festival in the HD version, complete with balloons, confetti and giant swinging axes.
• Autobots, Rock Out!: The first half of the Perfect Chaos battle and the Theme Music Power Ups that occur in Shadow's Rival Battle are all accompanied by Crush 40. On top of that, you have the option of replacing the default theme of any level, even the Final Boss, with any of the available Sonic music they unlock, which just so happens to include Open Your Heart, It Doesn't Matter, Live and Learn, Sonic Heroes, What I'm Made Of, I Am (All of Me), His World, Endless Possibilities, and Reach For The Stars.
• Auto-Tune: The classic remix of "Escape from the City" has it, though it's justified because it's there to pay tribute to and match the pitch of the Endless Mine melody.
• Automatic New Game: Selecting "New Game" from the title menu immediately takes you to Green Hill Zone Act 1.
• Awesome, but Impractical: Super Sonic loses rings at a faster rate than usual. The modern version can now fly through levels in a manner similar to the Chaos Control ability in Shadow the Hedgehog. Unfortunately, doing so drains rings ridiculously fast, limiting its usefulness. Classic Super Sonic is also not that much faster (if any faster at all) than Modern Sonic.

• Baby Talk: Very slightly with Classic Tails in the HD version, who has an adorable lisp and says "w-" when he means to say "r-" occasionally. Also applies for the other language settings. He's supposed to be a younger version of Modern Tails, after all.
• Badass Adorable: Classic Sonic, basically being a smaller and cuter Sonic and kicking about as much ass as his modern counterpart.
• Bad Future:
  • Metal Sonic’s boss battle in the HD version takes place in the Bad Future version of Stardust Speedway, where the sky is dark and Eggman's facilities have destroyed the local flora.
  • Crisis City takes place in the future, where an insane sun god has ravaged most of the world and turned it into a lava-covered wasteland.
• Bag of Spilling: In Colors, (Modern) Sonic can double jump and jump forever underwater. In Generations, he's lost both moves without any explanation.
• Big Badass Rig: The GUN Truck, making its triumphant return from Sonic Adventure 2. Unfortunately, it now has sawblades and can fly.
• Big Bad Duumvirate: The Time Eater is treated as the main villain for most of the plot. Just before the Sonics finally confront him, it's revealed that the monster is actually subservient to both Modern and Classic Eggman.
• Birthday Beginning: The game kicks off (and ends) at Sonic's birthday party.
• Blank White Void: The Hub Level is a white dimension beyond the limits of time and space where assorted zones from the previous games can be accessed.
• Bonus Feature Failure: The ability to name your skill sets in the HD version for easy identification is a good idea in theory. But here, you cannot use the PS3 or XBox360's keyboard feature and must instead choose two terms from a long, unalphabetized list. That in itself would not be unbearable, but after choosing two terms, they are automatically separated by an ampersand, unless the first term is "Skill Set" and/or the second term is a letter (the default naming scheme). Nearly every catchy title you can think of for your Skill Sets will be blemished by that obtrusive "&". Even PC gamers are stuck with this.
• Book Ends: The game begins and ends at Sonic's party.
• Border Patrol: Modern Sonic can run across the surface of Seaside Hill's ocean in the HD version, but if he runs too far off the main path for a couple seconds, the giant Chopper from Green Hill leaps from the water to snap him up.
• Bottomless Pits: They exist, but like in Sonic Colors, you get a helpful warning sign alerting you to their presence. In tune with the tendency of this game to make call backs, said warning sign is the original Sonic death sprite.
• Bowdlerise: Unlike in Sonic Adventure 2, City Escape has only parked cars as Modern Sonic, meaning that you don't get to wreck occupied cars. Arguably a rare positive example, since it doesn't feel in-character for Sonic to go directly causing accidents that should lead to deaths en masse...
• Breaking the Fourth Wall:
  • Both hedgehogs look at their totals during their Act Clear endings, as well as the "Mission Cleared" text in the 3DS version's mission completion screens.
  • Both Sonics can also jump onto the titles of each level; in fact, doing so is how you get to the fight with Shadow.
• Brick Joke: Sonic's chilli dog is sent flying away at the beginning of the game. When Sonic returns from the White Void, he finds himself at the exact point in time that preceded his abduction, allowing him to catch his meal before it hits the ground.
• The Bus Came Back: Several supporting characters return with speaking roles after years of absence. This includes the entire playable cast of Sonic Heroes (except Omega and Big), as well as Silver and Blaze.
• But for Me, It Was Tuesday:
  • Modern Sonic remarks to Tails that the Time Eater's handiwork is nothing special, considering the genies in magic books and interstellar amusement parks they've dealt with in the past. Sonic sounds almost resigned to his status as a Weirdness Magnet when delivering the line in question.
  • After defeating the Egg Dragoon, Sonic brings up how routine Eggman losing to him has become.
• Call-Back: The game script does a couple of nods to other adventures, mostly Sonic Colors which is Ken Pontac's debut as a writer for the series.
  • Near the beginning, Sonic makes a call back to Sonic and the Secret Rings and Sonic Colors in the same sentence:
    Tails: This place looks like something sucked out of life and color of it. Totally strange.
    Sonic: No stranger than rescuing genies in magic books or saving aliens in an interstellar amusement park.
  • At one point Sonic repeats a line almost directly from Sonic Colors:
    Cubot: (in Colors) Your plans have been crushed by Sonic for, like ever. He stops you like it's his job or something.
    Sonic: (in Generations) Seriously, we beat this guy every time. It's like it's our job or something.
• Call-Forward:
  • Classic Sonic has several Skills that reference the abilities and shields he can use past the original game. One of his last Skills is the Homing Attack, a move that Modern Sonic can already use naturally.
  • In the 3DS version, Classic Sonic learns the Homing Attack (from himself) earlier, at the start of the Modern Era. At the end of the game, he instead learns how to use Modern Sonic's Sonic Boost, although the ability is unusable as a Skill.
  • Tails doesn't recognize Green Hill Zone, since he hadn't been introduced into the series yet.
• CamelCase: Sonic the Hedgehog CD's Japanese soundtrack's music for the present time period of Palmtree Panic can be unlocked and the song has the title capitalized as "PalmTree Panic."
• The Cameo:
  • City Escape in the HD version is packed to the brim with them. The names of some modern characters appear on a Chao in Space 2 ad. Some older faces, like Bark, Bean, and Fang, appear on wanted posters. Even Mighty and Ray can be spotted (on "Missing since 1993" posters, no less).
  • Orbot and Cubot appear in Eggman's flashback to The Stinger of Sonic Colors, which also explains why they are otherwise absent from Generations.
  • Big, Omega, Princess Elise, Mephiles, Chip, Dark Gaia, and the Werehog appear briefly in archival screenshots in the credits.
  • Omega gets another cameo in Speed Highway, as one of the roads is 123 Omega Road. 123 is his number in the "E" Series.
  • Look carefully at the beginning of both stages of Planet Wisp and you'll see some White Wisps. There's even one in Classic Planet Wisp who dances exactly like Yacker does in the Loading Screens of Colors!
  • Statues of Jet and all three types of Chao can be unlocked in the Statue Room.
• Captain Obvious: Of a peculiar kind. During the fight against the Time Eater in the HD version, a lot of Sonic's friends kindly remind you "That looks like a homing shot," but only Shadow says "That's a homing shot" with certainty.
• Cardiovascular Love: Rouge's challenges in the HD version require using her charm attack, which consists of her blowing heart symbols at Egg Pawns to make them lower their guard.
• Casino Park: Casino Night Zone, in both versions (though it's only a proper level in the 3DS version).
• Chainsaw Good: The GUN truck, which comes equipped with three giant buzzsaws this time around in the HD version's Modern Sonic portion.
• Chekhov's Gag: The signpost from Classic Crisis City passes by in the foreground a little while after it's first blown away.
• Chekhov's Gun: There's some effort hiding Dr. Eggman from the player on the Death Egg Robot boss in the HD version and the Big Arm boss in the 3DS version, especially when he "kidnaps his past self" by Time Eater.
• Collection Sidequest: The Red Star Rings in the HD version, returning from Sonic Colors.
• Colour-Coded for Your Convenience: Temporary platforms are associated with the color red.
• Concept Art Gallery: Includes music and art.
• Continuity Nod: Being a game all about Sonic's history, there's loads of it. Now has its own page.
• Continuity Porn:
  • The entire game is this, as it features levels from just about every major Sonic game in the series as well as games not in the major series, including Sonic CD.
  • Even more so considering the nature of the game as a sequel to the events of Colors; direct continuity is something rarely seen in more recent Sonic titles, so having it established and directly referred to in a game all about Sonic's history is a notable achievement on Sonic Team's part.
  • In the English version, the game even acknowledges the Eggman/Robotnik debacle when Classic Eggman states that no one calls him by his real name anymore. (He was always Eggman in Japanese, so that exchange is absent there.)
• Cool Board: Classic Sonic has a skateboard, in true early 90s fashion. Modern Sonic uses a snowboard in City Escape, just like old times, as well as in a mission in Rooftop Run. Also, the ability to use a skateboard at will is one of the unlockable skills for Classic Sonic.
• Crisis Crossover: The current, green-eyed Sonic meets his retro, black-eyed self through Time Eater's disturbance of the time holes. Both hedgehogs must team up to fix Sonic's timeline and defeat the Time Eater.

• Credits Medley: Much like the old Sonic games, the credits roll has music from every stage that ends with the old Sonic theme.
• Cute Mute: Classic Sonic does not have a voice actor, but is no less expressive than his Modern counterpart; it helps that he's officially Modern Sonic as a young child, and thus he has an innocent quality to him.
• Cutting Off the Branches: Metal Sonic's Rival Battle heavily implies that the Metal Sonic race in Sonic CD took place in the Bad Future. ^note While one could argue that the Time Eater may be responsible for Stardust Speedway appearing in its Bad Future state, note that the beginning of Sonic 4: Episode Metal also has Metal Sonic in the Bad Future, which also heavily implies the race took place there.
• Damn You, Muscle Memory!:
  • If you're used to the Homing Attack on the HD versions of Sonic Unleashed^* where it was shared with the 'Boost' button (X on 360 and Square on PS3), you may have to readjust yourself to the standard Homing Attack controls used in all the other Sonic games for Generations HD^* Pressing the 'Jump' button (A on 360, X on PS3) in mid-air to perform it.
  • There's also the issue of trying to do a Homing Attack as Classic Sonic and trying to do a Spin Dash as Modern Sonic.
  • Anyone who was used to playing Colors on the Wii's Classic Controller may have difficulty pressing the slide/stomp button without instinctively reaching for the Y/Triangle button.
  • The double-jump in Colors isn't present in Generations (double-tapping the jump button as Modern Sonic does the forward-air-dash move), which can seriously screw the player up when they accidentally try to double-jump up to a higher platform.
  • invokedStealth Attack. Complete the level without defeating enemies. Good luck keeping yourself from using the homing attack.
• Darker and Edgier: Compared to the rest of the stages, Crisis City sticks out as a much darker stage. The stage is set in post-apocalyptic world, and the enemies are demonic monsters instead of Eggman's cartoonish robots.
• Dead Character Walking: There is an infamous glitch which crept from the infamous Sonic the Hedgehog (2006) to the otherwise excellent Sonic Colors and Sonic Generations which makes Sonic, if he receives mortal damage while on a autoscrolling sequence, still slide with his dead body on the track. He can even be controlled sometimes with the directional pad!
• Death Throws: When you lose a life as Classic Sonic, aside from bottomless pits.
• Deflector Shields: In addition to the regular shield the Flame, Aqua, and Thunder Shields return from Sonic 3 & Knuckles in certain missions and can be equipped in any main level once said missions are completed. The bounce, flame dash, and spark jump capabilities are fully intact. They no longer deflect projectiles, though.
• Demoted to Extra: While the regulars of Sonic's ensemble cast makes an appearance in the game, they have next to no impact on the story—by and large only the two Sonics and Tailses get Character Focus. The ensemble cast get a brief cutscene for being rescued, a couple of dedicated challenge missions, the ability to dispense advice about the game, and the opportunity to cheer Sonic on during the final boss. A little egregiously, Sonic doesn't even talk to anyone aside from Classic Sonic or Tails.
• Department of Redundancy Department: In a cutscene after Chemical Plant in the HD version, Modern Sonic says that he's getting "deja vu all over again," paraphrasing a famous quote from Yogi Berra.
• Design Student's Orgasm: The game's menu screens feature a mess of abstract shapes and bright primary colors decorating their borders, most obviously with the act title cards. It's an homage to the Japanese box art of the 16-bit games, which had a similar aesthetic.
• Developer's Foresight:
  • Hilariously, hitting a Crabmeat in Green Hill will cause it to dance happily at being able to hit Sonic for the first time in twenty years.
  • Classic Sonic's idle animations includes one that has him pointing to the right. He even does this when facing left, except with his thumb instead of with his finger.
• Did You Get a New Haircut?: Several characters make remarks along these lines if rescued as Classic Sonic. For two more literal examples:
  • Cream asks Classic Sonic this upon being rescued.
  • Upon being rescued, Blaze wonders if Classic Sonic has gotten less spikey, i.e. has less hair.
• Did You Just Punch Out Cthulhu?: Modern Sonic facing Perfect Chaos while not in Super Mode.
• Difficult, but Awesome: One unlockable skill for Modern Sonic, Endless Boost, provides you with a Boost Gauge that never runs out, but also turns Sonic into a One-Hit-Point Wonder, unable to collect any rings. While it's supposed to be a Take That! at the notion that Modern Sonic gameplay is simply "boost to win", this ability allows the player to do some major Sequence Breaking in Seaside Hill, and rewards speedrunners who have managed to learn how to use the Boost to swiftly get through stages without being harmed.
• Distracted by the Sexy: One of the extra missions involves robots who block themselves with shields, and the only way to destroy them is to summon Rouge the Bat to distract them so that they can't block your attacks. That's right. Rouge is so sexy that not even robots are immune to her charms.
• Divergent Character Evolution:
  • As Green Hill Zone has been brought back, Seaside Hill has understandably taken many liberties to differentiate itself from the zone it was originally supposed to be a throwback to. Most notably, it's incorporated some aspects of Ocean Palace from Heroes^note which was effectively Seaside Hill's Act 2 as well as added a water section. Planet Wisp, another level meant to hearken back to Green Hill, also more heavily leans into its Eternal Engine theming than the original game.
  • A lot of the other zones got upgrades to their unique features and obstacles. For example, City Escape's skateboard section and park areas were lengthened and expanded, and the truck was given an upgrade, so it's now less like Speed Highway.
  • Since the HD version of Generations runs on the same engine as Unleashed, this game's version of Rooftop Run is made more distinct from the original by giving it an Attack of the Town Festival vibe, with festive banners and balloons interspersed by attacks from a Flying Battery-esque airship. Classic Sonic's route also takes some inspiration from the night version of the stage, particularly adding a segment within a wine cellar, despite otherwise taking place during the day.
• Double Jump: Classic Sonic can do one with the Thunder Shield.
• Double Unlock: Many skills require you to first complete a specific challenge, then buy it from the store.
• Do Well, But Not Perfect: Some of the Red Star Rings require you to take a lower path, going against regular Sonic logic to always take the highest path.
• Drives Like Crazy: In the classic version of City Escape, the GUN truck that chases Sonic around the city while plowing into buildings and making huge ramp leaps starts getting noticeably worn down and beaten up about halfway through the level, and during the climax it appears so damaged that it's hurdling helplessly into a bridge underpass and is totaled when it crashes. As it turns out, driving like a maniac won't do your ride any favors.
• Driving Up a Wall: During the last leg of the GUN Truck chase in City Escape, the souped-up GUN Truck sprouts rocket boosters and continues to chase Sonic on the walls of buildings he runs on, before eventually destroying itself by crashing into another building as Sonic escapes through a narrow alleyway.
• Dub-Induced Plot Hole: Inverted: in The Stinger, the two Eggmen are seen arguing over the fact they haven't found the door one of them claimed to have found. The English version, which was written first, ends on a silent scene that shows Modern Eggman pointing angrily at Classic Eggman while the latter's throwing a fit. The Japanese version extended the dialogue to fill that silence, thus explaining why they're making those gestures.
• Early Installment Character-Design Difference: A retroactive case for the Classic Sonic Dimension. The Badniks ^note  Moto Bugs, Buzz Bombers, Crabmeats, Choppers, Newtrons, Buzzers, and Eggrobos encountered by Classic Sonic in both versions of Sonic Generations ^note  Console and 3DS share the same "Modern" design, compared to the more faithful "Classic" designs they would later have in Sonic Mania, though the Classic Buzzers themselves wouldn't be part of it.
• Eldritch Abomination: The Time Eater◊, a psychotic-looking (seemingly) mechanical being that's covered in a cloud of dark energy and features clockwork parts. All the gears and the purple smoke body may remind you of another children's game eldritch abomination...
• Eldritch Location: Time Eater's boss arena, a cloudy reddish-purple void filled with floating props from the previous levels (trees and mountains from Green Hill, the G.U.N truck from City Escape, etc.), and giant golden clockwork parts.
• Embedded Precursor: Sonic 1 is an unlockable game within the console version.
• Energy Weapon:
  • The Cyan Laser Wisps return in Tropical Resort in the 3DS version.
  • The Time Eater fires lasers in the final battle.
• Epic Fail:
  • At the end, not only is Modern Eggman stranded in an infinite space void of time with Classic Eggman, but he accidentally convinces Classic Eggman to give up on villainy entirely and pursue a career in schoolteaching. Oddly enough, Modern Eggman approves.
    Modern Eggman: That's not a bad idea! I've always enjoyed telling people what to do!
  • Then again, Classic!Eggman seems to have facepalmed when Modern!Eggman said that, so he may not have actually gone through with it.
• Eternal Engine:
  • Chemical Plant is a completed one, while Planet Wisp is also well on its way, as it's being constructed on an idyllic alien planet.
  • Eggmanland, which serves as the the battle arena against the Egg Dragoon, is a vast factory complex that spreads throughout a continent controlled by Eggman.
• Evil Is Not a Toy: Subverted for once. Pretty much every 3D Sonic game before and since this one has had Dr. Eggman attempt to use or control another being to further his goal of taking over the world, only to inevitably get betrayed near the end. In this game, Eggman harnesses the power of the Time Eater and takes control of it for his own use... and is completely successful, never getting betrayed by the creature at any point.
• Evil Laugh: Lampshaded by Classic Eggman as Modern Eggman laughs hysterically.
  Classic Eggman: Wow. Will I really get that crazy?
• Evil Laugh Turned Coughing Fit: In the console version, after Dr. Eggman is done explaining his plan to destroy Sonic, he begins to laugh maniacally, but has to stop halfway through to cough into his hand.
• Excuse Plot: A giant monster has caused Sonic's friends to become lost in time, and Sonic has to team up with his past self to race through locales from his earlier adventures in order to save them! No problem with that!
• Exposition Fairy: Omochao. There is an option to turn him on/off, however.
• Face on a Milk Carton: The fate of Mighty and Ray, with posters on City Escape lampshading their disappearance from the franchise.
• Face Palm:
  • Modern Sonic, in response to Amy when he frees her.
  • Modern Sonic also has one when he finds out that Eggman is controlling the Time Eater, and is thus the Big Bad.
• Faceship: The Death Egg, which is visible in the distance during Sky Sanctuary and is the setting for the first boss fight (the appropriately-named "Death Egg Robot").
• Failure Is the Only Option: After the ending credits, Classic Eggman finds out that Modern Eggman has never beaten Sonic. He gets discouraged by this and decides to go get his teaching degree. Modern Eggman thinks that's not a bad idea, since he enjoys telling people what to do.
• Fastball Special: Vector's ability in his Co-Op mission.
• Final Boss: Hedgehog rivals aside, the boss fights are all final/true final boss fights from other Sonic games; the Time Eater is their successor for this game. The only exception to this is the Egg Dragoon (which was only the penultimate boss in Sonic Unleashed, although it did serve as the Werehog's Final Boss); it should also be noted that Shadow served as the Final Boss in Sonic Adventure 2's Hero Side story.
• Final Boss, New Dimension: The final boss is faced in an entirely new arena, complete with timepieces and a purple background.
• Finishing Each Other's Sentences: Done by Classic and Modern Tails sometimes. The Eggmen, as well.
• Flanderization: The truck in City Escape. Although in Sonic Adventure 2, the main purpose of the truck was probably to catch Sonic despite collateral damage. In Generations, it basically wants to kill and maim Sonic without any care for its surroundings (Because why on earth would a truck need three buzzsaws, rocket jets, and the ability to drive on the side of a freaking building?).
• Flight:
  • The Orange Rocket Wisps return in Planet Wisp in the console version.
  • Modern Super Sonic is capable of limited flight (much higher than the few inches above the ground usually associated with in-level Super), though it eats through rings too quickly to be very useful.

• Follow the Money: Naturally, especially evident when rings appear after hitting a switch.
• The Foreign Subtitle: In Japan, the 360/PS3 versions of the game are titled Sonic Generations: White Time and Space, while the 3DS version is titled Sonic Generations: Blue Adventure. In western territories, all versions of the game are simply titled Sonic Generations. Even so, both versions have a white or blue backdrop on the boxart.
• Foreshadowing:
  • Vector tells Classic Sonic he has a hunch that the Time Eater is actually being controlled by someone. He is proven to be correct later, when both versions of Eggman are revealed to have the monster under their control.
  • Compared to Classic Eggman's begging for help when he's captured after the Death Egg fight, Modern Eggman has no objections when the Time Eater grabs him after the Egg Dragoon battle and it takes place in a fraction of the time as the first. With the revelation that the Time Eater is controlled by the two Eggmen, one can see that the first fight was deliberately thrown and that the second was actually a rescue.
• Friendly Rivalry: Silver treats his Arena Battle with Sonic as a sparring session and seems to have a lot of fun whether he wins or loses.
• Fungus Humongous: Mushroom Hill in the 3DS version has gigantic mushrooms that Sonic can bounce on to reach higher areas.
• Future Me Scares Me: Classic Doctor Eggman is surprised at how maniacal his future self is. He's later disappointed to learn that Modern Doctor Eggman never defeats Sonic.
• Game-Breaking Bug:
  • In the PC version, it is literally impossible to play the game with most non-Xbox 360 gamepads. Due to a different input format between the 360 controller and other PC controllers, the game will interpret a non-360 controller as having random buttons fired at intervals, making Modern Sonic randomly quick-step left and right and cutscenes skip themselves (the game thinks that the player has pressed Start repeatedly when they haven't). The quick-stepping bug actually renders Seaside Hill Act 2 Unwinnable with a non-360 gamepad unless you hammer the boost button and get lucky.
  • The PC version has a couple of consistently-crash-causing spots. The most notable is Rouge the Bat's challenge for Modern Sonic in Seaside Hill, which has a very high chance to crash to desktop at any point during the stage.
  • Trying to access the online "Challenge Mode" can be an exercise in frustration, as something about the game's communication with the leaderboard data servers (which takes place every time the menu cursor is moved) causes it to almost always dump the user to the desktop with an error message when it tries to load record data.
• Game Mod:
  • A particularly epic one by a trio of programmers from Sonic Retro, who successfully ported the day levels from Sonic Unleashed into the PC version.
  • At the request of Arin Hanson in an episode of Game Grumps, a mod replacing Sonic's model with that of an actual hedgehog has been created.
  • And with the creation of utilities such as CPKREDIR and SonicGMI, this game's on its way to becoming one of the most easily moddable games for the PC.
  • There's a mod for the PC version that adds the "restoring colours as you run through the world" part of the story into the actual gameplay, removing the Gameplay and Story Segregation.
• Gameplay and Story Segregation: Even though it's said that running through the zones restores color and life to them, all of the zones seem to be full of color before you even start moving.
• Gameplay Roulette: There are two gameplay styles, but both of them are closely similar, unlike the wildly differing styles in Sonic Adventure and Sonic Unleashed, for example.
• "Get Back Here!" Boss: All three Rival battles, the Egg Dragoon, the Egg Emperor, and the Time Eater are fought this way.
• Glass Cannon: What the "Endless Boost" does for Modern Sonic. He can boost endlessly through enemies, but will die instantly if he makes contact with something his boost can't protect him from.

• Green Hill Zone: The Trope Namer returns in all its verdant glory, as do Seaside Hill and Planet Wisp.
• Hailfire Peaks: As in Sonic Colors, Planet Wisp combines the Green Hill Zone motif with an Eternal Engine. Crisis City is Lethal Lava Land mixed with After the End. Most of the levels are combined tropes, really, considering it's a Sonic game.
• Hammerspace: Lampshaded by Modern & Classic Tails after the final boss. Specifically, where Sonic keeps all those rings he collects.
• Heroic Mime: Classic Sonic. The 3DS game, which has text boxes to make up for having less voice acting, only has punctuation like "?," "!," and "..."
• Hijacked by Ganon: The Time Eater is really just a creature transformed into a manned machine by Classic and Modern Eggman.
• Hoist by His Own Petard: Silver ultimately loses his rival battle by being crushed by the gigantic ball of debris that he tried to attack Sonic with.
• Hub Level: The 360/PS3 version skirts the line by having one big 2.5D White Void Room Hub that serves as an "interactive menu" for selecting levels/bosses, talking to Sonic's friends, accessing extra content, etc. Within the narrative, Tails explains that said void is where the stages end up falling into after the Time Eater distorts their position in time and space.
• Human Cannonball: There are cannons which shoot Sonic out of them on Seaside Hill.
• Humongous Mecha: The Death Egg Robot, Egg Dragoon, and Egg Emperor. The Time Eater is also revealed to be one.
• Idle Animation:
  • Classic Sonic still glares at the player impatiently when idle. He may also occasionally cross his arms in frustration, snap at the player and point to the right, look at his wrist, and lay on the ground after a while.
  • Modern Sonic's animations are from Unleashed and Colors, plus a unique idle animation if he's standing in water.
• I Got Bigger: Classic Sonic and Tails are Modern Sonic and Tails as young children.
• Indy Escape: Both acts of City Escape have you pull one to escape from the GUN truck, while Seaside Hill Act 1 has a more conventional example as Classic Sonic outruns a giant cylindrical rock that chases him towards the goalpost, crushing everything in its path.
• Interface Spoiler:
  • People looked at the Xbox 360 Avatar rewards for beating the game and speculated that Classic Eggman has a link to the Time Eater, since said Avatar parts are all patterned after Classic Eggman. They were right.
  • In the 3DS version, provided the player has at least 5 Play Coins, they can unlock mission 100 without ever starting the Story Mode. Said mission is to beat the final boss under a rather forgiving time limit.
  • The 3DS version tries to hide the existence of Classic Eggman by blacking him out on a certain icon on the touch screen.
• Internal Homage: Tons of them. Rooftop Run (originally from Sonic Unleashed) has zipline platforms like in Sonic 2's Hill Top Zone and dropping platforms with spikes on them like in the original game's Marble Zone. And the Classic level ends with what appears to be Sonic & Knuckles' Flying Battery, complete with Eggman logo.
• Invincibility Power-Up: Invincibility is back for both hedgehogs.
• Innocuously Important Episode: Despite being an anniversary celebration game and having dozens of nods to previous games, Generations comes off as rather episodic, and its events are ignored by the next game. Cue the 25th anniversary celebration, in which it's revealed that the Classic Era from this game has become a separate timeline of its own (possibly as a result of the time travel that took place in this very game) that gets revisited in Sonic Mania and its accompanying web miniseries Sonic Mania Adventures, in addition to Classic Sonic briefly returning in Sonic Forces.
• Irony: Tropical Resort is the first stage in Sonic Colors, but in the 3DS version of Generations, it is the last stage.
• Lampshade Hanging:
  • Crabmeats do a little happy dance and fall laughing when they hurt Sonic.
  • Modern & Classic Tails have a conversation about where Sonic actually puts all of those rings, with Modern Tails mentioning that he keeps forgetting to ask.
  • One of the tutorial images has Omochao rambling on next to an annoyed Sonic.
  • Right before the final battle, Classic Tails refers to Classic Eggman as Dr. Robotnik. Classic Eggman replies in a matter-of-fact way that nobody calls him that anymore.
• Large Ham: Spanish Sonic. Also, German Doctor Eggman (Hartmut Neugebauer) has been acknowledged by Sonic Team to be the perfect voice for the good doctor. To be fair, he's also the standard German dubbing voice for a certain other large ham.
• Law of 100: The game returns to giving an extra life at 100 rings, which had been not used in Sonic Colors.
• Lazy Artist: In the 3DS version, Classic Sonic's first three zones are copied directly from the original games' first acts, instead of the wholly unique layouts seen in other zones. Mushroom Hill in particular has a useless checkpoint right before the goalpost, since the miniboss was removed but the layout wasn't changed.

• Leitmotif: A music piece that accompanies the Big Bad.
• Level in Boss Clothing: Perfect Chaos plays out more like a regular stage with some opportunities to hit the boss, with both 2D and 3D platforming segments that Chaos isn't really involved in, and checkpoints when no other boss has them.

• Literal Ass-Kicking: How Classic Sonic deals damage to the Death Egg Robot boss in the HD version in the first phase of the battle.
• Loads and Loads of Loading: The PS3 version. Load times average 20 seconds both entering and exiting stages and missions, including the momentary pause for the game to auto-save to the hard drive after every level. Especially noticeable as most of the challenge stages are extremely short.
• Long Song, Short Scene:
  • The "Goin' Down!?" theme from Sonic Adventure received a full minute-long remix, but because this game's version of that sequence is heavily abridged, the in-game version is cut to only a fraction of that.
  • The Super Sonic theme of this game is as long as the equivalent themes from other games and even loops, yet it only plays briefly in the cutscene prior to the final boss (and not when either Sonic transform outside of said boss fight). It, incidentally, is a remix of Sonic the Hedgehog 4's theme, the only apparent nod to that game in Sonic Generations.
  • Cash Cash's remix of the Big Arm theme is three and a half minutes long. The boss should take the average player about 30 seconds to beat.
  • "Perfect Chaos Revival" from Sonic Adventure receives an extended remix, but only plays for about twenty seconds tops during the actual boss battle.
• Lost Food Grievance: That poor chili dog... At least it comes back eventually.

• Marathon Level: The Planet Wisp levels have Sonic running through grassy hills, exploring Eggman's base of operations, and finally using the Wisp Powers to ascend to the facility's upper areas. Without exploiting glitches, a competent player can take as much as 6 minutes to complete each of these acts, making them twice as long as every other level in the game.
• Meet Your Early-Installment Weirdness: Sonic, Tails, and Dr. Eggman meet themselves as they appear in the Genesis games.
• Megamix Game: When a game consists almost entirely of Nostalgia Levels and Legacy Boss Battles, it's one of these.
• Mercy Mode: The Nintendo 3DS version of the game's Time Attack mode and the Challenges in the other versions counts as this. Previous handheld Sonic games' time attacks sent you straight to the "retry/change-zone/change-character/quit" menu after either finishing the level or dying, but in Generations this happens only after having completed the stage; dying results in either restarting the stage or respawning at the last checkpoint instead. This means you can practice sections as much as you please. However, respawning at a checkpoint doesn't set the timer to whatever time you happened to run past said checkpoint. So, if scoring a perfect time is your top priority, you have to restart the level manually.
• Metropolis Level: The game neatly demonstrates just how common this level type is in the franchise: the console and PC version includes Speed Highway, City Escape, and Crisis City, while the 3DS version includes Radical Highway.
• Mirror Boss: The Rival Battle with Shadow. Until one of them gets a power-up, or Sonic falls too far behind Shadow, the two hedgehogs basically have identical abilities, boosting included.
• Mirror Routine: Classic Sonic's and Modern Sonic's first introduction to each other. They were separated by a warped piece of glass, so it's actually somewhat believable.

• Mission Control: Omochao, to some extent. All of Sonic's friends join in as well in the final boss battle, calling out incoming attacks.
• Model Museum: The character models for Sonic, Classic Sonic, Tails, Classic Tails, Eggman, Classic Eggman, Classic Metal Sonic, Shadow, Silver, Knuckles, Amy, Blaze, Cream, Cheese, Rouge, and the Chaotix are able to be viewed in the Collection Room with a short bio describing each character.
• Monochrome to Color: The Hub Level shows each level in white (as each act has been frozen in time), and gradually becomes more colorful as you clear both acts.
• Monster of the Week: A tradition since Sonic Adventure, Time Eater is the one for this game. Subverted: it was a monster but it's turned into a manned robot by Dr. Eggman with the help of his past self.
• The Mother Ship: Classic City Escape's GUN truck can dump off more Mooks on Classic Sonic.
• Moving the Goalposts: In Classic Crisis City, a tornado literally does this by moving the goalpost to a later part of the level, forcing Sonic to chase it.
• Multi-Slot Character: The basic premise of the game is that Sonic's classic and modern versions are both playable characters each with their own gameplay style based on the era their from.
• Multi-Stage Battle: During the final boss battle, the debris floating around the arena is from the previous stages, and the era they're from changes each time you hit the boss. (i.e. Classic Era at the beginning, Dreamcast Era after the first hit, and Modern Era after the second hit.)
• Museum Game: The game is basically traveling through the past of Sonic, with a lot of extras on the side. It contains levels themed entirely after locations from previous games in the Sonic the Hedgehog franchise. There's also a gallery of concept art, information on characters in the series, and the ability to earn music from the series.
• Musical Nod:
  • Classic "Escape from the City" has a brief remix of Endless Mine, from Sonic 3 and the melody of the City Escape trial version.
  • Modern's version of "Escape from the City" uses pieces of the theme for the Snowboard Race multiplayer level and "It Doesn't Matter" from Sonic Adventure 2.
  • An entire section of Modern Seaside Hill is practically devoted to remastering Ocean Palace. That's right, they haven't just subliminally seduced you with the use of putting traits from older Sonic series selections into newer songs, but they mashed-up two themes from Zones of the same category!
    • On that note, Classic Seaside Hill greatly resembles the Nintendo DS version of Sonic & Sega All-Stars Racing's Seaside Hill.
  • A remix of "Door into Summer" from Knuckles Chaotix is the theme for the Collection Room.
    • The song that plays for Classic Sonic's Ring Time power-up is a remix of the special stage theme from Knuckles Chaotix.
  • Modern Sky Sanctuary lifts its extended bits directly from the Mario & Sonic at the Olympic Winter Games rearrangement of Sky Sanctuary.
  • The cover of "Super Sonic Racing" samples this Sega Saturn promo; more precisely, the lines "I have arranged for you to meet my... companion," "Introducing Sega Saturn!" and "We are five years away from entering the 21st century... but are you ready for the future?"
  • Sega pulled us a rather tricky one with this one: Super Sonic's theme begins with the intro of Live and Learn, only to be followed by a remix of Sonic the Hedgehog 4's main theme.
  • Does the theme for obtaining an S Rank sound familiar? It's a remix of a verse from Sonic's Adventure theme.
• Musical Spoiler: The identity of each boss is hidden until you fight them. However, standing in front of the boss gate will play a remix of the boss's respective battle music, giving away the boss's identity to any Sonic fan familiar with the games' soundtracks. This is downplayed by the third boss: Egg Dragoon's "preview track" is "E.G.G.M.A.N.", which indicates that it's Eggman but not any particular form of his.
• Mythology Gag:
  • Sonic shredding air guitar should look familiar to anyone who has seen Sonic Underground.
  • In the opening cutscene, Classic Sonic can briefly been seen having a sharp fang in his mouth. This is an obvious nod to his early concept art, which depicted him as having fangs.
  • Vector sets up a venue in one of the Modern Rooftop Run challenges, with him playing the keys. In the scrapped Sonic Band◊, he was the keyboardist.
  • Sonic calls himself "the fastest thing alive" in one of the first cutscenes in the 3DS version, a reference to the opening theme from Sonic the Hedgehog (SatAM).
• Nerf:
  • In the console and PC version, the Sonic Boost's ring-attracting effect has been greatly reduced from Unleashed and Colors.
  • It's now impossible to sustain an Air Boost (Sonic will simply act as if you quickly tapped the Boost button), so it's nothing more than a more powerful Air Dash that retains momentum. The 3DS version averts this and the ring-attraction nerf, however.
  • Also as Super Sonic, the boost ability greatly exhausts your ring count. Compare to Sonic Colors where the player would not only maintain the more gradual ring loss, but actually earn bonus points for using the Super form in the first place. That said, the ability is far more useful in Generations due to its Chaos Control-like abilities and the more fluid stage design in general.
• Never Trust a Trailer: Apart from the launch trailer, none of the CGI shown in the trailers exists in the game. In fact, the trailer at the start is the only cutscene to use CGI; the rest use gameplay models.
• Never Say "Die":
  • Dr. Eggman says how he is going to turn Sonic into blue jelly.
  • When Sonic sees himself in a mirror, Dr. Eggman says he better get a good look, because it's the last thing he will see before Eggman "closes his eyes forever."
• invokedNo Death Run: Completing an act without losing any lives is encouraged because it gives you a Perfect Bonus, which boosts your rank by one full letter grade. In the main levels, the coveted S rank is only attainable by giving an A-rank performance with no deaths.
• Nostalgia Level: Every level in the game is derived from old Sonic games, though the level design is mostly new. It works both ways; Modern Sonic plays through classic stages with the new style of gameplay, and Classic Sonic plays through newer stages with nostalgic gameplay.
• Not Bad:
  • Knuckles admits that Sonic "wasn't half-bad" after the final boss is defeated.
  • Eggman taunts Sonic with this line during his boss battles.
• Not so Fast, Bucko!: In Act 1 of Crisis City in the HD version, as you approach the goal sign, it gets carried away by a flaming tornado.
• Offscreen Moment of Awesome: No explanation has been given for how Dr. Eggman or his past counterpart Dr. Robotnik escaped from the timeless void leftover from the destruction of the Time Eater in the ending. They got out of there somehow as future games attest, but how they did it when they had access to absolutely no technology is left up in the air.
• Oh, Crap!: Classic Sonic has no dialogue, but his expression at the Time Eater's initial appearance is definitely this.
• Ominous Latin Chanting: The words sung in Modern version of Time Eater's battle music are Dominus Tempus, roughly translated from Latin to "Master of Time"; fitting Time Eater's role in the game.
• One-Hit Kill:
  • Sonic can run over the water by boosting. In Seaside Hill Act 2, there is a giant chopper that attacks if you spend too long outside of certain areas. If it attacks, you lose a life, no matter what. Rings? Won't help you? Going as fast as you can? Won't help you. Even Super Sonic can't survive a contact with it!
  • The meteorites that fall near the end of Tropical Resort Act 2 kill Sonic in one hit regardless of his rings. At least they're telegraphed.
• Oxygenated Underwater Bubbles: Chemical Plant's Mega Mack features these, unlike the original level. Seaside Hill also has them, which is, again, a new thing as Seaside Hill's original iteration had no underwater gameplay.

• Pinball Zone: Casino Night. It's a full-fledged world in the 3DS version, but just the setting for a pinball minigame in the console version.
• Place Beyond Time: The Blank White Void, as Eggman points out when he and his past self get stuck there.
• Playing Tennis with the Boss: One side mission requires you to bat music notes back and forth with Vector.
• Playing with Fire:
  • The Red Burst Wisps return in Tropical Resort in the 3DS version. Holding the jump button will store power, then releasing it unleashes a fiery explosion that destroys every enemy on-screen.
  • The Fire Shield power-up from Sonic 3 finally makes a return. It still allows Sonic to perform a fire tackle.
  • Iblis' minions return in Crisis City. Much like in the original game, they are lava monsters that breathe fire to attack.
• Plot Armor: When the Time Eater crashes Modern Sonic's birthday party it opens up a set of portals that capture everyone at the birthday party in an inescapable vortex... except for Sonic himself, who doesn't even have to adjust for the breeze.
• Pop-Star Composer: Alex Makhlouf, of Cash Cash, does a few remixes for the game.^* If you really want to know the specific remixes he did, according to the OST's booklet they are: Classic Speed Highway, "Going Down!?", Classic City Escape, "Super Sonic Racing" and US Stardust Speedway for the console version; Classic Radical Highway, Modern "Back 2 Back" (Water Palace), Big Arms and the Special Stages for the 3DS version. Tony Harnell and Ted Poley also returned to sing a new version of "Escape from the City".
• Power Copying: Classic Sonic picks up on the homing attack after seeing modern Sonic use it against a few enemies in the 3DS version. He can use it from that point on.
• Powerup Magnet: The Thunder Shield magnetizes rings in addition to providing Sonic with a double jump.
• Press X to Not Die: In the 3DS version, there is a QTE when escaping from the killer whale in Emerald Coast Act 2.
• Red Alert: Used during Chemical Plant's meltdown in Modern Sonic’s level.
• Retcon:
  • Even more of this occurs with Crisis City, as when Blaze is rescued, her first speech balloon post-cutscene has her state that Crisis City was her fault.
  • Given the ending of Sonic 06, the fact that Crisis City exists at all when a time travel incident erased the events of the game from existence by removing Iblis from the timestream long before the game takes place counts to an extent. The implication seems to be that Crisis City was taken from another timeline, which would also explain the presence of Stardust Speedway's Bad Future.
  • After beating the Biolizard in the 3DS version, Sonic claims that he's beaten it before, although it was actually Shadow who fought it last time (in Sonic Adventure 2). (He may have been referring to its subsequent form as "The Finalhazard", but he was explaining why he found the fight so easy, so that wouldn't have made a great deal of sense in context.)

• The Rival: Shadow, Silver, and Metal Sonic are rival races on the 3DS version. On the console, they are proper boss fights.
• Rule of Cool: Three of the four bosses in the HD version make sense story-wise as to why they're there. The fourth? Perfect Chaos, who is presented as a Giant Space Flea from Nowhere without any connection to the main plot. Pretty much the only reason it's in the game is for the sheer awesome of the boss fight.
• Sampling: The JP Stardust Speedway remix samples the original JP Bad Future Stardust Speedway and JP Present Stardust Speedway, which in turn made extensive use of sampling classic '70s and '80s songs ("Love's Gonna Get You" by Jocelyn Brown, "Me and Baby Brother" by War, and "Hey Y'all We're Miami" by Miami, among others).
• Scenery Porn: Lots, as is to be expected in a Sonic title, with Sky Sanctuary being a breath-taking revamp from a classic level.
• Scenery Gorn: Crisis City and the ruined Station Square in which you fight Perfect Chaos are ruins of previously prosperous cities that have been decimated by two vicious gods of destruction.
• Sequence Breaking: The last segment of Modern Planet Wisp revolves around Sonic ascending a huge tower to reach the goal ring. However, if the player has a Rocket Wisp on hold, they can activate it immediately after going through the jump panel that launches Sonic towards the tower's base, thus skipping a huge section of the level.
• Shout-Out:
  • City Escape has new billboards that include a mock iPhone.
  • The first part of Modern Sonic's S Rank pose is based on Usain Bolt's "To Di World" pose◊.
  • The NiGHTS Resort re-appears in Radical Highway.
  • One of Planet Wisp's challenging acts features all three elemental shields. The mission itself is called "With Your Powers Combined".
  • The hardest achievement is called "Can't Touch This".
  • In the 3DS version, some missions will require you to get through an entire stage without losing a single life. All missions of this type are titled "Die Hard".
  • In Speed Highway, one of the billboards advertises a movie called Chao In Space: The Search for Tikal.
• Shown Their Work:
  • Classic Sonic looks exactly like the original Sonic design from the Genesis games, starting with the coloring details (black irises and flesh-colored eyelids), all the way to the animations and sound — even the Cheeky Mouth looks identical. He’s closer to his smaller and cuter Japanese design, as opposed to his attitude-infused Western design used on the box-art for the US versions of the original Sega Genesis trilogy (which Sonic Team admittedly hated).
  • All of the Classic Character designs featured in the game are based off of previous artworks: Classic Sonic, Classic Super Sonic◊, Classic Tails, Classic Metal Sonic, Classic Eggman.
  • Not only were the writers of the game's script not Sonic fans themselves, they didn't even know much about the franchise in general. They made up for it by researching the lore of the franchise, and it shows considerably (due to the sheer amount of Continuity Porn added throughout the game).

• Soundtrack Dissonance:
  • This peaceful theme plays during a few Co-Op missions. Even in Crisis City's.
  • The game lets you invoke this by allowing you to switch out the BGM of a stage or boss for any song you have unlocked in challenges. Yes, you are fully allowed to fight Perfect Chaos to the sound of Emerald Hill Zone if you really want to.
• Sprint Meter: The Auto-Gauge skill turns the Boost Meter into this.
• Stable Time Loop: The ending shows Classic Sonic attempting to perform the Air Dash/Homing Attack, suggesting that he learned it by watching his future self do it in an earlier cutscene.
• Stealth Pun: In the classic stage of Speed Highway, Sonic can jump into the church bells to make them ring. Doing so also produces rings out of thin air that he can collect.

• Suddenly Always Knew That: Many special character-based missions feature the character demonstrating heretofore unseen abilities.
  • Blaze's character missions in Crisis City and Planet Wisp features Blaze outright flying like a bird seemingly without the aid of the Sol Emeralds or her Pyrokinesis. At no point was it ever hinted that she possesses such an ability.
  • Amy Rose has historically had several Spin Attacks and in Sonic Heroes could draw out her airtime by using the Hammer Helicopter technique after jumping. In Generations, however, Amy is now so proficient with spinning her hammer that she can now hover and fly anywhere and at will.
  • Rouge, who has always been a Shameless Fanservice Girl, newly demonstrates the ability to actively seduce any robot she sets her eyes on.
• Super Drowning Skills:
  • Oddly, Modern Sonic zigzags this, depending on the viewpoint. When transitioning to a 2D section with liquid, he works exactly how he handles in Colors (minus infinite jumping). However, in full 3D segments, he drowns instantly if he falls into any liquid.
  • In the 3DS version, the water sections in Emerald Coast are deadly, yet the ones in Water Palace can be safely traversed.
• Surprise Party: The game begins with Sonic's surprise birthday party.
• The Stinger: After the credits, we see Modern and Classic Eggman bickering inside the Hub Level, now completely emptied by the restoration of the timeline.
• Straight Man and Wise Guy: Classic!Eggman is the calmer, more reserved Straight Man to the crazier and more dynamic Modern!Eggman. Lampshaded when Classic Eggman questions his own sanity in the future after he sees Modern Eggman breaking into a Laughing Mad fit.
• Tactical Suicide Boss: The Death Egg Robot is fought in an arena with mines classic Sonic can activate to stun the boss. No matter how many times he's damaged, he will still do this. Though with the ending, it's obvious he was throwing the fight.
• Taken for Granite: What the Time Eater does to Sonic's friends.
• Taught by Experience: Eggman makes sure the Monster of the Week is completely under his control by mechanizing it, instead of failing to control it like in most previous games.

• Tennis Boss: Vector, in one of Rooftop Run's Challenges as Modern Sonic. You have to reflect the music notes at him until he loses track and you win.
• Theme Music Power-Up:
  • In the Rival Battle with Shadow, when either Sonic or Shadow goes on the offensive, the music switches to Live and Learn or All Hail Shadow, respectively.
  • When Classic and Modern Super Sonic combine to strike the final blow on the Time Eater, the music changes to the Sonic 4 invincibility theme.
• Time Travel: The two Sonics travel through stages of their past in an attempt to restore time.
• Tomorrowland: Stardust Speedway takes place during what was Sonic CD's bad future.
• Took a Level in Badass:
  • Modern Sonic proves how much he has grown across the years by defeating Perfect Chaos without the need of transforming into Super Sonic.
  • Rooftop Run highlights the fact that Clasic Sonic will become much more badass in the future. The final hurdle for Classic Sonic is climbing a very tall clock tower, fighting off lots of badniks and performing tricky jumps along the way. When Modern Sonic has to perform the same task, he just runs straight up it in a matter of seconds.
  • Silver's psychic powers are shown to be considerably more powerful in this game than they've ever been shown to be before, allowing him to condense a massive amount of debris into a massive sphere that he hurls at Sonic. He's also much faster, easily able to keep up with a boosting Sonic.
  • In the span of a single game, Eggman went from simply enslaving an alien race to power a theme park, to transforming an Eldritch Abomination into a Humongous Mecha that rips apart time and space.
• Unflinching Walk: After Classic Sonic defeats the Death Egg Robot and it falls over, he lands on his feet in a badass pose.
• Variable Mix:
  • The BGM in Modern Sonic's Green Hill and Sky Sanctuary stages have a percussion track that changes tempo depending on how fast Sonic is moving. Also, the high-pass filter effect when boosting carries over from Sonic Unleashed and Sonic Colors.
  • The speed shoes return in Classic Sonic's stages, so naturally the tempo picks up while using them.
  • The Death Egg Robot has two additional drum tracks as the fight progresses.
  • The Time Eater's theme seamlessly changes styles according to which Super Sonic is in control; from an orchestral style for Modern Super Sonic to an electronic style for Classic Super Sonic.
  • The hub world, which has a mix based on every stage in the game.
• Video Game Perversity Prevention:
  • The skill set names can only use two preset words instead of allowing for player input, and while the "&" that's always added to them seems completely unneeded, it does prevent any potential innuendos the players could use the available words for. If you tried naming your skill set "Love Maker", you'd get "Love & Maker" instead.
  • The character bios in the trophy room specifically do not allow you to rotate them more than waist-height, preventing you from using it to look up Amy and Cream's skirts.
• Villain Team-Up: Eggman teams up with his past self to take full control of the Time Eater's abilities.
• The Voiceless: Classic Sonic, keeping with the spirit of the Genesis games. Oddly enough, Classic Tails and Classic Eggman do talk.
• Voice for the Voiceless: Classic Tails speaks on Classic Sonic's behalf.
• Wall Crawl: The Pink Spike Wisps return in Planet Wisp on the console version. Modern Sonic can also run along (and up and down) walls in Speed Highway and City Escape.
• Wall Jump: Can be done on certain surfaces as Modern Sonic.
• What Happened to the Mouse?: It's never explained what happened to Orbot and Cubot when Eggman found the Time Eater. It's assumed he just left them in space, and returned for them in time for Sonic Lost World.
• Xtreme Kool Letterz:
  • The "Mad Skillz" achievement.
  • One of the words available to name your Skill Sets with is "Skillz".