Start the game with the "avp.exe -debug" command line parameter.
 Now open the console and type in the codes (Attention, saving the
 game is not possible in debug mode):

 All characters:

 GOD                     Invulnerability
 GIVEALLWEAPONS          All weapons
 ALIENBOT                Spawns an alien
 MARINEBOT               Spawns a Marine
 PREDOBOT                Spawns a Predator
 PREALIENBOT             Spawns a Predator alien
 PRAETORIENBOT           Spawns a Praetorien lien
 XENOBORG                Spawns a Xenoborg
 LIGHT                   Spawns light
 OBSERVER                Invisibility
 SHOWCOORDS              Show coordinates
 SHOWFPS                 Frame rate
 SHOWPOLYCOUNT           Polygone countzer
 LISTCMD                 List of cheats
 LISTVAR                 Online help
 TIMESCALE <0.0-1.0>     Changes game speed
 SKY_RED                 More red to the sky
 SKY_BLUE                More blue to the sky
 SKY_GREEN               More green to the sky
 LEANSCALE               Changes sidestep range
 CALVINRULEZ             Greetings from the programmer

 Alien only :

 THEONEDEADLYCREAUTUREEVERCREATED       Invulnerability
 WINNEROFTHEONEGREATBATTLEOFTHEUNIVERSE Invulnerability
 CROUCHMODE <0 OR 1>                    Crouch and crawl mode ON/OFF

 Marine only:

 FREAKOFTHEUNIVERS                 Invulnerability
 MOTIONTRACKERVOLUME <0.00-1.00>   Volume of the motion tracker
 MOTIONTRACKERSPEED  <0-16>        Speed of the motion tracker

 Predator only:

 SKULLCOLLECTOR                    Invulnerability
 GIMME_CHARGE                      Full energy