Press [~] and type in one of the following codes (confirm with [Enter]):

 Command                      Effect
 -------------------------------------------------------

 iwillsurvive                 God mode
 takeittothelimit             Unlimited ammo
 hitmewithyourbestshot        Computer wins
 raindropskeepfallinonmyhead  5 shoots with artillery
 closetoyou                   Toggle AI
 sky                          Turn OFF clouds textures