Men In Black

During the game press 'ESC' then type in 'DOUGMATIC' until you are taken back to the game. Then hit 'ESC' again and type in any of these cheats...

Protectme God mode
Loadme Unlimited ammo
Giveme All weapons
Arctic Arctic level
Healme Full health
Hq Headquarters
Killem Kill villains
Moveme Saved games of all levels
Agentj Agent J
Agentk Agent K
Agentl Agent L