While developers and publishers typically strive to ensure that every game makes it out the door (or at least every game they've announced,) many simply don't make it over the finish line for various reasons. As a result, the project will be cancelled, usually leaving only press releases, interviews, and/or preview screenshots and trailers for the game to be remembered by.
Rarely, a tangible product from a cancelled game will find its way out into the wild. Sometimes these become collectors' items, other times they are copied and released onto the Internet for fans and archivists, and, in rare cases such as Sonic X-treme for the Sega Saturn, fans will sometimes attempt to complete cancelled games.
Very rarely, albeit more commonly since the 2010s, games which were once cancelled will be un-cancelled, finally seeing release or being re-imagined into a retail product.
- Games listed must have been shown to the public in some form (playable, trailer, official formal announcement) either online, at an event, etc., only to never see retail release.
- Rumored titles, (i.e. Mutant League Football 2009 or Pokemon 64,) should not be included here; only games that were officially confirmed by a game studio to have been in development at some point in time.
- Titles that never officially ended development according to the developer or publisher should not be included. Announced games which simply disappeared from the public eye are considered to be vaporware.
- Once a game is cancelled, it should not have any associated links (i.e. concepts, locations, objects, etc.) Franchise, developer, and publisher associations should remain, provided they were known.
- Games whose multiplayer servers have been shut down, as well as discontinued MMOs, do not qualify. They should be tagged as their respective concepts instead.