Infinite Ammo:
Repeatedly press L + R + Down.

Invisibility:
Repeatedly press L + R + A + X.

All Drugs and $10,000:
Repeatedly press L + R + left thumbstick button.

Mission Skip:
Repeatedly press L1 + R1 + X.

Show Drug Stashes:
Repeatedly press L + R + Left.

Show Hidden Stashes on Radar:
Repeatedly press Press L + R + Left.

The Refinery:
Repeatedly press L + R + B + A.

Unlock Bonus Mission:
Collect all 25 secret stashes in Asia.

Unlock Original 1988 Arcade NARC:
Collect all 25 secret stashes in USA.