An author, developler, or a group of them start with a basic idea, and from there start building a new work intended to be released to the public, but sometimes these author(s) may see that their creation isn't working like they intended to, it's missing a little ''something'' in it. Maybe the creators are not very talented in the genre or media they used to start their work, maybe those just don't, or flat out can't, show the work the way they intended to, or maybe it's just for a [[ExecutiveMeddling meddling executive]] getting involved.

Whatever the reason, they see that the bases they have chosen for their work just aren't working the way they want to, so it's time to change one or more of these bases before they release anything.

This can come in two flavors:

* '''Genre shift:''' The work keeps its grounds on the same media, but changes its style to other of the many genres inside that media, like from Comedy to Drama in {{Theater}}, or a Platformer to Action Adventure in VideoGames.
* '''Media Shift:''' Unusual but not unheard of, this one generally occurs during the first moments of the work's creation, and regularly means that the author's goal for this work just wasn't expressed well in the media chosen. For example, the author could have started with his work in written media, but then (s)he sees that without visuals it feels incomplete and/or that a fitting BGM could do a much better job conveying the feelings that (s)he intends to show; or maybe started with some sort of visual media, but later thinks that using more reader's interpretation and less "this is how it was and looked like" is a better option for his intentions.

Don't confuse with GenreShift, CerebusSyndrome, ReverseCerebusSyndrome, and CerebusRollercoaster, which are changes during a work's run instead of before its release. Subtrope of WhatCouldHaveBeen.
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!! Examples:

[[foldercontrol]]

[[folder: Anime And Manga: ]]

* ''Anime/MagicalGirlLyricalNanoha'' was originally intended to be a straight MagicalGirl series, but ended up somewhat closer to HumongousMecha show with cute girls once it was released.

[[/folder]]

[[folder: Comic Books: ]]

* ''The Griff'' was written by ChristopherMoore and Ian Corson. It started as another Moore novel, but when he realized the idea was too visually dependent for the written word he set it aside - until the opportunity to make a graphic novel arose.

[[/folder]]

[[folder: Fan Works: ]]

* ''WebAnimation/TurnaboutStorm'' started out as a written fanfiction, but as it progressed evolved to an attempt at a game in order to be able to put music in it, then to a radio play, and finally to it settled with ''VisualNovel/AceAttorney'' game-walkthrough-like videos so visual elements could be added.

[[/folder]]

[[folder: Film: ]]

* ''Film/CoolWorld'' was originally intended to be a horror film, but ExecutiveMeddling demanded a more family friendly plot and basically rewrote it.
* ''Film/DrStrangelove'' was originally meant to be a straight drama, much like the original novel, but Creator/StanleyKubrick found the situations so ridiculous and over the top that he decided to [[PlayedForLaughs play it for]] [[DarkComedy dark laughs]].
* ''Film/MulhollandDrive'' was originally going to be a TV series. The first two thirds (made for TV) are nowhere near as surreal or adult oriented as the climax (made to wrap everything up as a film).
* ''Film/GoodWillHunting'' was originally conceived of by Matt Damon and Ben Affleck as a thriller, before the Weinsteins encouraged them to instead emphasize the relationship between Will and his psychologist.
* Seen in the Korean movie ''Windstruck'' (the loose prequel to ''Film/MySassyGirl''), which veered from RomCom to Fantasy to Tragedy and back again.
* ''Film/{{Zombieland}}'' was originally intended to be a [-TV-] series.
** And now it will become one, due to ''Zombieland 2'' being canceled by the studio.
*** [[StillbornFranchise Yeah, about that...]]
* ''Dear Diary'' - a ShortFilm - was a sitcom pilot that wasn't picked up. Won an [[AcademyAward Oscar]] for Best Short Subject.
* ''Film/{{Beetlejuice}}'' was originally supposed to be a horror movie, but was changed to a supernatural comedy.
* ''Holiday Inn'' was originally to have been produced on Broadway as a plotless revue.
* ''Disney/TheEmperorsNewGroove'' was originally conceived as a dark musical film instead of a lighthearted comedy film with only one or two songs. And [[BigBad Yzma]] was originally going to have her own song.
* Jason Friedberg and Aaron Seltzer's ''Disaster Movie'' started life as a ''{{Superbad}}'' parody called "Goodie Two Shoes", but for whatever reason changed to a loose parody of ''Film/{{Cloverfield}}'' in the middle of production.
* In-universe example: In ''Film/ShakespeareInLove'', Shakespeare starts writing a comedy named "Romeo And Ethel, The Pirate's Daughter", which later becomes the well known tragedy ''Theatre/RomeoAndJuliet''.

[[/folder]]

[[folder: Literature: ]]

* ''FearAndLoathingInLasVegas'' was originally just going to be a straight series of articles covering a motorcycle race in Las Vegas, before becoming the weird, wacky, genre-defining whatever-it-is that it became.
* StephenKing admitted that he didn't know where ''Literature/{{Christine}}'' and his short story ''The Library Policeman'' were going when he wrote the first several pages, but both started out considerably lighter and more comedic than they ended up.
** ''TheMist'' and ''Apt Pupil'' both underwent a slight media shift from short story to novella due to a case of "literary diarrhea".

[[/folder]]

[[folder: Theatre ]]

* ''{{Company}}'' was originally written by George Furth as a cycle of eleven short plays.
* ''{{Theatre/Wicked}}'' was originally supposed to be an {{Aida}}-esque romance, the core of the story being the relationship between Fiyero and Elphaba, with Glinda essentially a supporting character. The finished story instead focused on the RomanticTwoGirlFriendship, making Fiyero more of a SatelliteLoveInterest.

[[/folder]]

[[folder: Video Games: ]]

* ''{{Halo}}'' was originally conceived as a RealTimeStrategy game, but it made it to shelves as a FirstPersonShooter, probably because its plot and factions coupled with its genre would have made it too similar to RTS heavyweight ''{{Starcraft}}''. [[HaloWars They eventually revisited the RTS idea, though]].
** Also, the developers changed genres because they decided they wanted to play as the soldiers. Initially Halo was a third person shooter for Macs (which can be seen in early videos and screenshots) but became a first person shooter when Bungie was purchased by Microsoft.
* A light variation with ''SonicTheHedgehog'', the initial concept was a more traditional platformer with puzzles and exploration akin to ''VideoGame/SuperMarioBros2''. The final product, while still a platformer, focused more dominantly on its now trademark speed. This evolution is even more prominent in [[VideoGame/SonicTheHedgehog2 its sequel]].
* According to [[http://www.cracked.com/article_19457_6-baffling-early-prototypes-your-favorite-video-games.html Cracked]], the NES version of ''SuperMarioBros'' [[http://kotaku.com/5668710/super-mario-used-to-shoot-bullets was going to be a shoot-em-up platformer]], and Mario was going to carry guns, [[http://us.wii.com/iwata_asks/mario25th/vol5_page1.jsp like the beam gun]] similar to those in ''{{Metroid}}'' and a rifle. [[HilariousInHindsight Also, he was going to]] [[VideoGame/SuperMario64 punch and kick enemies while empty-handed]], [[VideoGame/SuperMarioWorld ride on clouds]] (which were previously {{r|idingTheBomb}}ockets in earlier development) and fire at enemies in cloud drive-bys that would soon become [[BonusStage bonus coin stages]]. Also, the "jump button" was going to be "up" on the Control Pad, leaving the "A" button open for attacks.
* {{Rareware}} has a habit of doing this:
** ''{{Banjo-Kazooie}}'' was originally conceived as ''Dream'', a 2D SuperNintendo RPG with human characters rather than a 3D FunnyAnimal platformer.
** ''VideoGame/GoldenEye1997'' was originally to be an on-rails light-gun shooter like ''Lethal Enforcers'' or ''VirtuaCop''. Before that it would have been a pre-rendered 2D platformer, like ''VideoGame/DonkeyKongCountry'' but with guns. The unrelated GameBoy James Bond game is much closer to this design.
** ''VideoGame/ConkersBadFurDay'' was originally just another generic kiddie platformer before they retooled it into the rude, crude, offensively over-the-top game everyone knows and loves. This was ''after'' the tie-in Game Boy game, which really was as saccharine as Conker was intended to be, had been released as well.
** ''VideoGame/StarFoxAdventures'' started off as an original IP titled ''Dinosaur Planet'' before ExecutiveMeddling told them to retool it into a ''Star Fox'' game, complete with {{shmup}} sections and [[HijackedByGanon a surprise final boss]] that were so very obviously tacked-on near the end of production.
* ''[[VideoGame/RavingRabbids Rayman Raving Rabbids]]'' was conceived as a Rayman 2-esque platformer with original creator Michel Ancel having full involvement, but ExecutiveMeddling caused the switch to a minigame collection and Ancel being dropped from the project.
* ''VideoGame/MetalGear'' began development as a straightforward shoot-'em-up, cashing in on the popularity of Capcom's arcade game ''Commando'', but the programmers were having too much trouble creating a similar game on the [=MSX2=] since the hardware couldn't handle too many enemy soldiers and bullets on-screen at the same time. When HideoKojima was brought into the project to salvage it, he decided to shift the game's focus to avoiding combat.
** ''VideoGame/MetalGearSolidPortableOps'' started development as an online multiplayer deathmatch-style shooter unrelated to the main ''Metal Gear Solid'' storyline. ''Portable Ops Plus'' does include the online multiplayer though.
** ''VideoGame/MetalGearRisingRevengeance'' originally was named ''Metal Gear Solid: Rising'' and was a stealth-action game that emphasized hunting enemies. When the game switched developers from Kojima Productions to Creator/PlatinumGames, the stealth aspect was toned down in favor of more straightforward combat (hence the title change), though some stealth remains as the player can kill enemies without them expecting it.
* ''{{Shinobi}}'' began development as a game about shooting shurikens at enemies from a first-person view. The developers planned to include a shuriken-shaped paddle to control the player's aim. The concept didn't prove to be that interesting and Sega decided to revamp ''Shinobi'' as a side-scrolling action game, with the shuriken-throwing game idea used for the bonus stages instead.
* ''VideoGame/{{Thief}}'' started life as an Authurian-legend swashbuckling game with minor emphasis on stealth (with the tentative name ''Dark Camelot''.) Once Looking Glass Studios realized just how GOOD they made stealthing (ie, enemies not able to see you in the dark and having to be aware of your footsteps), they made a game specifically tailored for the mechanic, instead.
* The ''Videogame/RobinHoodPrinceOfThieves'' game for the NES by Sculptured Software was initially conceived as an action-RPG titled ''The Legend of Robin Hood'' that originally [[DolledUpInstallment had nothing to do with the movie]]. The game's publisher, Virgin Interactive, [[ExecutiveMeddling forced the developers to make it into a more straightforward action game after tacking on the movie license.]]
* ''VideoGame/TeamFortress2'' began as a realistic, serious FPS that was going to be just like [[VideoGame/TeamFortressClassic its predecessor]], but with more realistic physics. Then in 2003, they retooled it into a sci-fi FPS entitled ''Invasion'', which involved a humans vs. aliens plot. Finally, in 2006, the game was retooled into the humorous, cartoonish, lighthearted FPS we all know of today.

[[/folder]]

[[folder: Western Animation: ]]

* ''TheDreamstone'' was initially conceived as DarkerAndEdgier storybook with more action and mystical concepts. While some of these concepts make it into the finalized TV series (especially the pilot episode), the setup was reinvented into a more light-hearted RoadRunnerVsCoyote style cartoon.
* ''WesternAnimation/FamilyGuy'' flip flops with this throughout its development. Its prototype short ''The Life of Larry'' was something of a faux sitcom and had already invented the cutaway setup and heavy pop culture humor. The second prototype, a What-A-Cartoon short ''Larry And Steve'' played more along the lines of a Creator/TexAvery style kids cartoon, with the satirical humor being much more subtle. In it's intitial run ''FamilyGuy'' played something of a mix of both, utilizing the original cutaway and parody humor, but maintaining heavy use of light hearted slapstick. Following its [[UnCancelled UnCancellation]] however, the show slowly evolved into a [[BlackComedy shock value]] SadistShow.
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