Wolfenstein 3D Cheats
All versions
ILM - Hold down I, L, and M at the same time to give you 100% health, both keys, and 99 ammo, but you lose all
    your points and 10 minutes are added to your time
[TAB]# - Hold down the [TAB] key with one of the following to perform its respective effect: 
      G - Invulnerability 
      E - Ends the current level 
      B - Changes the border color 
      M - Displays memory usage 
      I - You get some points, health, ammo, and the next few weapons up (repeatable) 
      S - Slow motion 
      Q - Immediately quits to dos 
      C - Displays some level statistics 
      H - You take a hit 
      W - Level warp 
      F - Shows your co-ordinates (does not change) 
      T - Shows some weird information, supposedly about the sprites 

Version 1.0 or below only
NEXT - Must start game with the command parameter '-NEXT' to enable cheats (i.e. WOLF3D-NEXT)
[CTRL] + [TAB] + [ENTER] - Hold down these keys while in the game to enable/disable cheats
[TAB]# - Hold down the [TAB] key with one of the following to perform its respective effect: 
       N - No clipping mode (you can walk through walls) 
       O - Shows an overhead map 

Version 1.1 or above only
GOOBERS - Must start game with the command parameter '-GOOBERS' to enable cheats (i.e. WOLF3D -GOOBERS)[ALT] + [SHIFT] +
[BACKSPACE] - Hold down these keys while in the game to enable/disable cheats
[TAB]# - Hold down the [TAB] key with one of the following keys to perform its respective effect: 
        V - Adds VBL's. I found that the more there were, the more jerky the game got 
        X - Extra items (anyone want to elaborate?)