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