Type in the following code during gameplay (Use the console as in quake 1):

• give all-besides putting the above in your inventory also gives you 999 of the following: Environment Suit, Data CD, Power Cube, Pyramid Key, Data Spinner, Security Pass, Blue Key, Red Key, Commander's Head, and Air Strike Marker.
• give all-All Items
• give blaster-Blaster
• give bullets-Bullets
• give cells-Cells
• give grenades-Grenades
• give grenadelauncher-Grenade Launcher
• give invulnerability-Invulnerability
• give jacketarmor-Jacket Armor
• give machinegun-Machinegun
• give mines-Mines
• give nuke-Nuke
• give quad-Quad Damage
• give rebreather-Rebreather
• give rockets-Rockets
• give rocketlauncher-Rocket Launcher
• give shells-Shells
• give shotgun-Shotgun
• give slugs-Slugs
• give sshotgun-Super Shotgun
• give silencer-Silencer
• god-God Mode
• noclip-No Clipping
• notarget-No Target Mode