Long-running series often have to experiment a little before they find their niche: sometimes there are concepts abandoned early on that were fascinating, either because they were potentially good ideas back then, or they just clash too much with the later tone of the series. In short, the first installment is like a prototype. The first rough draft for a book.
This is particularly common in television, where the pilot episode is usually filmed long in advance of a show's actual debut. This gives the studio and creative team a chance to evaluate what worked and what didn't and make significant changes, including replacing cast members. In particularly dramatic cases, a series can undergo something of a Retool between its pilot and the debut episode (if the pilot isn't the debut episode itself of course).
If the series improves after abandoning these elements, it often leads to a Growing the Beard moment. For something similar applied to individual character personalities, see Characterization Marches On. A specific sub-trope of this dealing with early installments resembling the real world is Earth Drift. When early characters disappear entirely with no explanations, that's Chuck Cunningham Syndrome (or even Dropped After the Pilot, if it happens in the very first episode). Might be the result of Plot Tumors, Art Evolution and/or Early Installment Character-Design Difference and Continuity Drift.
There will always be some fans who view the current incarnation of a series as They Changed It, Now It Sucks!, but it also must be said that weirdness in this case isn't necessarily a bad thing. Plenty of ideas get scrapped in the natural course of a series, some of them perfectly good. Early Installment Weirdness might be synonymous with a time when a plot was more laid back, experimental, pre-Executive Meddling, pre-Flanderization, or any number of other things.
When this happens to themes, tropes or genres that become popular after the fact because of a work, and are only actually codified elsewhere, it is an Unbuilt Trope.
Compare New First Comics (where a webcomic establishes a new starting point that clashes with the actual beginning strips), Lost in Imitation (when later adaptations are influenced more by earlier adaptations than the source material), Early Installment Character-Design Difference (a specific form of Early-Installment Weirdness where a character's design in earlier installments is noticeably different from their later appearance), My Real Daddy (where other writers who handled a character are held in higher regard than the one who actually created the character), Breaking Old Trends (where a series drastically changes its established formula), Adaptation Displacement (where more people are familiar with the adaptation than the source material), and Early Adaptation Weirdness (when earlier adaptations look odd when compared to modern takes on the franchise). Contrast First Installment Wins and Later-Installment Weirdness. When a character displays this, it's Characterization Marches On (or Flanderization, when it essentially happens in reverse). May be the Oddball in the Series. This is very commonly found in works that were released before a Franchise Codifier. Often the cause of an Artifact Title. See also Meet Your Early-Installment Weirdness. If a piece of weirdness sticks around despite no longer fitting, it's usually The Artifact.
A special note: In video games, this is often the counterpart to Spiritual Successor. A series may evolve in a drastically different direction from its first installment in a technical sense, abandoning core gameplay mechanics or changing them in drastic ways, while retaining the setting (general background lore, characters, etc.), although elements can be added or retconned. This can happen if the developer for an intellectual property held by a publisher changes or merely if a developer wishes to keep a recognizable, established IP, but adapt to a new player demographic or emulate gameplay seen in another revolutionary title. Such changes result in an early installment weirdness when the sequels are compared with the first installment. In contrast, a game which tries to imitate a forerunner title mostly in gameplay terms (copying/refining particular "revolutionary" aspects, the entire gameplay or just the general "feeling" of the game), but is not part of the forerunners' IP, e.g. if the rights to the IP are held by a different publisher, and so uses a different setting, it's usually a Spiritual Successor.
Example subpages:
- Advertising
- Anime & Manga
- Comic Books
- Comic Strips
- Fan Works
- Fashion
- Films — Animation
- Films — Live-Action
- Let's Play
- Literature
- Live-Action TV
- Magazines
- Music
- Pinball
- Podcasts
- Pro Wrestling
- Radio
- Roleplay
- Tabletop Games
- Toys
- Video Games
- Web Animation
- Webcomics
- Websites
- Web Videos
- Western Animation
- Other Media
