While in game press "Enter" and type "<cheat> " (include the space 
after <cheat>), followed with the one of the codes from below and 
then press "Enter" to enable the code. 

Code                       Result 
-------------------------------------------------------------
mpcanthurtme             - God mode on/off
mpschuckit               - Add weapons and ammo
mpsmithy                 - Full armor
mpkohler                 - Full ammo
mpstockpile              - Full ammo
mpbeamme                 - Beam player to level start with initial conditions
mpsixthsense             - No clip on/off
mpicu                    - 3rd person mode on/off
mptachometer             - Show speed info on/off
mpsizeme                 - Show size info on/off
mpgrs                    - Show rotation info on/off
mpgps                    - Show position info on/off
mpfov                    - Edit (with keys) FOV value
mpvertextint             - Edit (with keys) vertext tint
mplightadd               - Edit (with keys) light amplification
mplightscale             - Edit (with keys) light scale
mpbreach Edit            - (with keys) weapon breach
mpwmpos Edit             - (with keys) weapon offset 1
mpwpos Edit              - (with keys) weapon offset 2
mpxfiles                 - Level select for all three species
mpdoctordoctor [number]  - Set health to indicated number
mpmorph [character type] - Change into indicated character type
mpmillertime             - Marines have slurred voice
mpdeathtoall             - Kill everything except your character
mpreloadbutes            - Reload an attribute file
mptriggers               - Toggle trigger boxes
mpmph                    - Displays framerate
mpconfig                 - Load new cfg file