From the help file of the patch 1:


 Normal Console Commands and Variables
 The following CONSOLE VARIABLES are made available (replace the # sign
 with a number), in-game help is available by typing the "LISTVAR" command
 at the console:

 MOTIONTRACKERVOLUME   this is set at its maximum of 1.0 by default, the
                       volume of the tracker can be reduced by changing
                       this number (e.g. to 0.75 or 0.5).
 CROUCHMODE            this new console command allows players to change
                       the Aliens crouch/crawl to a toggle on/off key by
                       typing "CROUCHMODE 1" at the console. "CROUCHMODE 0"
                       changes back to the default setting.

 Debugging Console Commands and Variables

 Advanced users may now access some of the game's internal debugging
 commands (which include features such as immortality) by running the game
 with the command line option "-debug" (e.g. "AVP.exe -debug").

 In this mode Multiplayer is not available, levels will not be flagged as
 completed, and no new official cheat modes will become available. This
 basically means that players can examine a level to which they already
 have access with invulnerability, infinite weapons, etc. but can't open
 up any new game levels or features.

 The following CONSOLE COMMANDS are made available by this option, in-game
 help is available by typing in "LISTCMD" at the console:

 GOD      makes the player immortal: player will still take damage, but
          will not die when they reach zero health.
 GIVEALLWEAPONS  self-explanatory
 SHOWFPS  displays the current frame-rate per second on-screen
 SHOWPOLYCOUNT   displays the number of rendered polygons per frame
                 on-screen
 LIGHT    creates a light source near the player. Repeated use makes a
          brighter and brighter light.

 Bot console commands:

 ALIENBOT      creates an Alien in front of the player
 MARINEBOT #   creates a Marine (or civilian) of type #
 PREDOBOT #    creates a Predator of type #
 PREDALIENBOT  creates a Predator-Alien
 PRAETORIANBOT creates a Praetorian Alien
 XENOBORG      creates a Xenoborg.

 Note: creating bots may cause crashes and unexpected game behaviour.
 For a bot to be created its model must exist in the current level;
 however, the models may be forced to be loaded through a command line
 option. Add "-l" followed by a list of letters corresponding to the
 characters you want to load:

 'a' Alien
 'm' Marine
 'p' Predator
 'c' Civilian
 'x' Xenoborg
 't' Praetorian
 'r' Predator-Alien

 e.g. "AvP.exe -lxc -debug" will cause both the Civilian and the Xenoborg
 models to be loaded (in addition to any characters that would get loaded
 for the level anyway).

 Note that all the letters must be in lower case, and that "-l" on its own
 will still cause the Alien to be loaded.

 The following CONSOLE VARIABLES are made available (replace the # sign
 with a number), in-game help is available by typing the "LISTVAR" command
 at the console:

 MOTIONTRACKERSPEED  allows the player to speed up/slow down the pulse
                     rate of the Marine's motion tracker (range from 0-16,
                     default is 1)
 TIMESCALE #         change the rate at which time flows in the game, e.g.
                     TIMESCALE 0.5 will make time pass at half the normal
                     speed. For those interested, the "JohnWooMode" cheat
                     uses this effect dynamically, so that time passes
                     slower the more action is happening on screen.
 WIREFRAMEMODE #     display the environment and/or characters using
                     wireframe graphics.
 DOPPLERSHIFT #      enable/disable the Doppler shifting on the Alien
                     player's sounds
 SKY_RED #           change the red component in a sky
 SKY_GREEN #         change the green component in a sky
 SKY_BLUE #          change the blue component in a sky
 LEANSCALE #         change the amount the camera tilts when side-stepping

 Here are some usefull chat line commands:

 EXPV         VERBOSE REPORTS OF TEXT EXPANSIONS
 LISTCMD      LIST ALL CONSOLE COMMANDS
 LISTEXP      LIST ALL TEXT EXPANSIONS
 LISTVAR      LIST ALL CONSOLE VARIABLES
 LISTBIND     LIST ALL KEY BINDINGS
 UNBIND-ALL   GET RID OF ALL KEY BINDINGS
 SAY          BROADCAST MESSAGE
 SAY_SPECIES  BROADCAST MESSAGE to your species
 CDSTOP       STOP THE CD PLAYING
 CDPLAY       SELECT A TRACK TO PLAY
 CDPLAYLOOP   SELECT A TRACK TO PLAY LOOPED
 CDVOLUME     SELECT SOUND LEVEL 0 TO 127
 ID_PLAYER    Get name of player nearest centre of screen
 SHOW_SCORE   Show frag table
 DETAIL_LEVEL_MAX  ?
 DETAIL_LEVEL_MIN  ?
 SCREENSHOT   SCREENSHOT
 EXTRAPOLATE_MOVEMENT  NETWORK OPPONENTS ON AND OFF

 -----
 Open the profile file from the sub dir \USER_PROFILES with a hex
 editor and overwrite the offsets 28 to 51 with 03. Now all charakters
 should be able to play all levels.