Go to the Episode 4 entrance and jump into the water. Now backup against the wall like you were going to go back the other way. Now stay against the wall and allow yourself to fall down. You should land on a big piece of wood. Walk along the left side to find another entrance that leads a to gate thats takes you to Nightmare Difficulty.
4/7/2002
Access any level
Open the console by pressing the key just left of the ''1'' button on the keyboard; then type ''map x'', where x is any of the following:
start - the introduction level, in which you select difficulty and which episode e1m1 - The Slipgate Complex e1m2 - Castle of the Damned e1m3 - The Necropolis e1m4 - The Grisly Grotto e1m5 - Gloom Keep e1m6 - The Door to Chthon e1m7 - The House of Chthon e1m8 - Ziggurat Vertigo (a hidden level) e2m1 - The Installation e2m2 - The Ogre Citadel e2m3 - The Crypt of Decay e2m4 - The Ebon Fortress e2m5 - The Wizard's Manse e2m6 - The Dismal Oubliette e2m7 - The Underearth (a hidden level) e3m1 - Termination Central e3m2 - The Vaults of Zin e3m3 - The Tomb of Terror e3m4 - Satan's Dark Delight e3m5 - The Wind Tunnels e3m6 - Chambers of Torment e3m7 - The Haunted Halls (a hidden level) e4m1 - The Sewage System e4m2 - The Tower of Despair e4m3 - The Elder God Shrine e4m4 - The Palace of Hate e4m5 - Hell's Atrium e4m6 - The Pain Maze e4m7 - Azure Agony e4m8 - The Nameless City (a hidden level) end - Shub-Niggurath's Pit
For example, type ''map e1m2'' to access the ''Castle of the Damned''.
6/24/2002
Cheat Codes
Press ~ to access the console, then enter the following: