Various cheats
     Hit the tilde button ~ (next to 1) and type in these cheats.

Cheat code:             Effect:
Disable_AI 1/0          Turns AI Off/On
Debug 1/0               Turns the Debug Menu On/Off
Gravity 1/0             Turns Gravity On/Off
Noclip 1/0              Turns Noclip On/Off
God 1/0                 Turns God Mode On/Off
FPS 1/0                 Turns Framerate On/Off