Often games are canceled in the very early stages of development leaving only a press release or preview in a magazine. But, sometimes, there is a tangible product associated with the canceled game which becomes a rare collectible. Sometimes these items are copied and then released onto the Internet for the fans, and, in rare cases such as Sonic X-treme for the Sega Saturn, attempts are made by fans to finish and release canceled games.
- Games that should be listed include ones shown in some form (playable, trailer, official formal announcement) either online, at an event, etc., but never saw 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 were never officially referred to with the word "cancelled" by the developers should not be included. They are considered to be vaporware.
- Canceled games should have no associated links (i.e. concepts, locations, objects, etc.) nor should they be attached to their respective franchise pages. Thus, canceled games' pages should exist on an island unto themselves for historical purposes only.
- Discontinued Massively Multiplayer Online Games have their own page, and should be listed there, not here.