To enable cheats, you need to add -cheats to the game's command prompt.
An easy way to do this is to right click on the game shortcut and choose 'Properties'.
In the 'Target' field, add -cheats to the end of the line. Now press
'Apply' and then start the game.
When playing, press Tab to open console and enter the following cheats:
max life Heals your characters
infinite ammo Unlimited ammunition
finite ammo Turns above cheat off
const life God mode
no const life Turns off god mode
kill enemy Kills all enemies on current location
ai off Turns enemy AI off
ai on Turns enemy AI back on
Thanks to Revolution reader Daniel Grunder!