Cheat Codes
If these cheatcodes don't work, be sure to upgrade to the latest version of AvP. Load the game with the "avp.exe -debug" command line and then while playing press ~ and enter one of the following:
God Mode(Marine) = freakoftheunivers
Become Final Xenomorph(Alien) = winneroftheonegreatbattleoftheuniverse
God Mode(Predator) = skullcollector
All weapons+ammo(all races) = giveallweapons
God mode(Any) = god
God Mode(Alien) = theonedeadlycreautureevercreated
Refill Energy Supply(Predator) = gimme_charge
Player invisible = observer