Cheats:
 
 Type them in whenever you need them:
 
 idbehold - Displays menu (followed by S, V, I, R, A, or L for choice)
 S=Strength (Berserk)
 V=Invulnerability
 I=Partial invisibility
 A=Full Automap (computer map)
 R=Anti-radiation suit
 L=Light amplification visors
 
 idchoppers - Gives you the chain saw
 idclev - Warp (followed by episode number and level number)
 idclip - No clipping (you can walk through walls)
 iddqd - Degreelessness mode (God mode)
 iddt - Toggles Automap between
 normal, full, and full with objects (enter when in Automap mode)
 idfa - Gives full ammo, 200% armor, and all weapons
 idkfa  - Very Happy Ammo (full ammo, 200% armor, all weapons & keys)
 idmus - Changes the music to a certain mission (followed by episode
 and level number)
 
 00 INTROA 01 RUNNIN 02 STALKS 03 COUNTD 04 BETWEE
 05 DOOM 06 THE_DA 07 SHAWN 08 DDTBLU 09 IN_CIT
 10 DEAD 11 STLKS2 12 THEDA2 13 DOOM2 14 DDTBL2
 15 RUNNI2 16 DEAD2 17 STLKS3 18 ROMERO 19 SHAWN2
 20 MESSAG 21 COUNT2 22 DDTBL3 23 AMPIE 24 TEHDA3
 25 ADRIAN 26 MESSG2 27 ROMER2 28 TENSE 29 SHAWN3
 30 OPENIN 31 EVIL 32 ULTIMA 33 READ_M 34 DM2TTL
 35 DM2INT
 
 idmypos - Displays your bearing and coordinates in hex