Press enter, then type the following codes. Notice the space between <cheat> and the actual code.

Code Effect

<cheat> mpschuckit All Weapons and Ammo
<cheat> mpmorph <character type> Change Character Type
<cheat> mpfov Edit FOV Value
<cheat> mplightadd Edit Light Amplification
<cheat> mplightscale Edit Light Scale
<cheat> mpvertextint Edit Vertext Tint
<cheat> mpbreach Edit Weapon Breach
<cheat> mpwmpos Edit Weapon Offset 1
<cheat> mpmillertime Edit Weapon Offset 2
<cheat> mpstockpile Full Ammo
<cheat> mpsmithy Full Armor
<cheat> mpcanthurtme Invincibilty
<cheat> mpxfiles Level Select for All Species
<cheat> mpsixthsense No Clipping
<cheat> mpgrs Rotation Display
<cheat> mpdoctordoctor <number> Set Health to Desired number
<cheat> mpgps Show Position Info
<cheat> mpsizeme Size Display
<cheat> mptachometer Speed Display
<cheat> mpbeamme Teleport to Start of Level With Default settings
<cheat> mpicu Third-person Mode
<cheat> mpbunker Unlimited Ammo