Hold [Left Shift] and press [Keypad Minus] at the indicated screen. Release the keys, then type one of the following codes to activate the corresponding cheat function.

Effect	Screen	Code
All missions unlocked	Main menu	campaign
End current mission	Game play	endmission
God mode	Any	iwillbetheone
Saves game	Game play	savegame
Show elevations on map	Main menu	topography