How to unlock every Doom episode and secret level
What you need to unlock episodes, secret levels and every weapon in the original Doom.
Original 1993 PC Doom campaign: Knee-Deep in the Dead, The Shores of Hell and Inferno. Shareware includes only the first episode. Ultimate Doom’s fourth episode, Doom II weapons and monsters, and modern port enhancements are outside this hub.
Episodes
All episodes in your copy are selectable from New Game straight away. Shareware Doom only includes Knee-Deep in the Dead; the registered game adds The Shores of Hell and Inferno, and The Ultimate Doom adds Thy Flesh Consumed.
Secret levels
Each episode has one secret level, map 9. Reach it by using the secret exit in E1M3, E2M5, E3M6 or E4M2. There is no menu option for map 9; IDCLEV can warp there directly.
Nightmare! difficulty
Nightmare! is listed on the skill menu from the start. Monsters respawn and move faster, and most cheat codes stop working.
All weapons
There is no weapon unlock; collect them in the levels or use IDKFA. The plasma rifle and BFG9000 are not in the shareware episode.
More Doom quick answers
Doom cheat codes: IDDQD, IDKFA and every PC codeWhere to find the Doom secret exits and secret levelsPistol-start each episode on Ultra-Violence for the intended challenge, then try Nightmare! once the maps are familiar.
Picture details
Game artwork belongs to its respective rights holders.