Hacx: Twitch 'n Kill

Hacx: Twitch 'n Kill (pronounced "hacks" and commonly shortened to just Hacx or written as HacX) is a total conversion for Doom II. The authors of the game paid id Software $5,000 for the rights to market Hacx as a commercial add-on for Doom II. Hacx was released by Banjo Software, the game's developer, after two and a half years of development in September 1997; in 2000, Hacx was re-released as freeware. Hacx uses a DeHackEd modified version of the Doom engine and features an entirely new set of levels, graphics such as textures, weapon sprites, enemy sprites, and the sprite for the player's character (Danny Evanger), sound effects, music, and voice-overs.