Start the game with the "-goobers" command line parameter. Then, press Left Shift + Alt + Backspace during the game and enter one of the following codes to activate the corresponding cheat function:
Change border color: Tab + B
Display number of items, doors, and actors: Tab + C
Skip two levels: Tab + E
Displays coordinates: Tab + F
Toggle God mode: Tab + G
Lose health: Tab + H
Free items: Tab + I
Display memory usage: Tab + M
Pause without message: Tab + P
Exit game: Tab + Q
Toggle slow motion: Tab + S
View graphics and play sounds: Tab + T
Add extra VBLs: Tab + V
Level select: Tab + W
Extra stuff: Tab + X