Men in Black

During the game, press esc. to get the main menu. type DOUGMATIC several times until 
it drops you back into the game.

the cheats are now activated.
Press esc. again

KILLEM - Kills Villians
GIVEME - All Weapons
LOADME - Unlimited ammo
HEALME - Full Health
PROTECTME - Invulnerablility
MOVEME - Gives saved games of all levels
AGENTJ - Become Agent J
AGENTK - Become Agent K
AGENTL - Become Agent L
AGENTX - Become Agent X
ARCTIC - Goes to Arctic Level
HQ - Goes to HQ