In its final "Ultimate" version, Doom had a total of four episodes with eight levels and a bonus level each (some home ports, like the Jaguar and Xbox versions, had additional stages). However, John Romero recently released many assets of Doom development to the public. Among the more fascinating artifacts of this development dump was a level labeled "E5M1", implying a fifth episode to the game was in production but ultimately scrapped. The opening shot (seen above) showed a hall of barrels near two Barons of Hell, implying this may have been a special challenge episode with no canonicity.
- An early pitch bible for Doom had a whopping six episodes in total.