Development hell is a term used to describe a game development cycle that, for whatever reason, has been struck with extensive delays. While the length of a normal game development cycle will vary depending on the type of game and the amount of effort and detail that the developers put in it, it is sometimes simply the case that plans fall apart and the game will require more time than expected to be put in a shippable state. Many games that enter development hell end up being cancelled, or otherwise quietly become vaporware.
No game is as emblematic of the idea of development hell as Duke Nukem Forever. Originally scheduled for release in the late 1990s, 3D Realms continuously delayed the game again and again until the company simply could no longer afford to work on it and halted the project in 2009. Shortly thereafter, Gearbox Software stepped in to help finish the game. Duke Nukem Forever finally shipped on June 10, 2011. It is one of the longest-lived projects to successfully escape development hell.