A new way of showing the credits, Development Hell is a rarely spawned level that can appear on Nightmare difficulty or above, and features a group of zombies with the names of the Diablo III game developers.
"Development Hell" is a reference to Development hell, an abnormally long period of development for computer games or other various forms of electronic media.
This crypt features a variety of zombies: Ravenous Dead, Retching Cadavers, Hungry Corpses. All monsters have the names and jobs of the game developing group. Two unique monsters are present in this dungeon: Jay Wilson and Josh Mosqueira.
Killing Jay Wilson grants a hidden achievement: "Smash, Jay, Smash", placed in "Feat of Strength" group on the achievement page, plus a sigil of a horned demon.