Cheat mode:
Hold R + G + K + O then enter one of the following codes to activate the corresponding cheat function. Note: The codes will not function if a joystick is present. 

Effect Code 
Full map  [Ctrl] + 1  
All weapons  [Ctrl] + 2  
Unlimited ammunition [Ctrl] + 3  
No damage  [Ctrl] + 4  
Access card for next level [Ctrl] + 5  
