While playing a game, press ~ to display the console window. Enter one of the 
following codes, then press [Enter] to activate the corresponding cheat 
function:

Result - Cheat Code
God mode - please god 
All weapons and ammo - please giveall 
Kill all monsters on level - please killall 
Open all doors - please open 
Invisibility - please invisible 
Restore energy - please refresh 
Flight mode - please fly 
No clipping mode - please ghost 
View all messages - please tellall