Knee-Deep in the Dead

Knee-Deep in the Dead is the first of the three episodes of Doom, the 1993 first-person shooter by id Software, each of which contains eight main levels; the other two are The Shores of Hell and Inferno. In it the marine fights demons and possessed humans in the military and waste facilities on Phobos, after a base there urgently requests military support and Deimos disappears entirely. The episode ends with the marine defeating two powerful Barons of Hell guarding a teleporter to the Deimos base. id published Doom as a set of three episodes under the shareware model and released this first episode free to market the full game.