Master Cheat List
On the title screen, press START and you will be able to select New Game, Load Game, Options, etc. Do these cheats on that screen.
Unlock all levels and movies - hold L + R, press DOWN, LEFT, DOWN, Y, DOWN.
Infinite ammunition - hold L + R, press UP, LEFT, DOWN, RIGHT, X.
Infinite shotgun - hold L + R, press RIGHT, X, X, X, B.
Always double handguns - hold L + R, press Y, X, UP, UP, UP.
Unlocks all disarm motions - hold L + R, press B, B, X, X, RIGHT.
One hit death - hold L + R, press DOWN, X, LEFT, LEFT, LEFT.
Sniper scope cheat - hold L + R, press B, B, B, DOWN, RIGHT.
Bang Bang cheat - hold L + R, press X, Y, B, X, RIGHT.
Stormtrooper Syndrome - hold L + R, press B, LEFT, Y, UP, DOWN.
No cursor - hold L + R, press UP, UP, DOWN, DOWN, UP.
Unlock Hard Boiled difficulty - hold L + R, press Y, B, LEFT, LEFT, X.
Unlock Super Cop difficulty - hold L + R, press B, Y, LEFT, UP, RIGHT. Unlimited Stamina (Shadow) - hold L + R, press X, B, Y, X, DOWN. Infinite adrenaline - hold L + R, press LEFT, RIGHT, LEFT, X, B.
Unlimited armour - hold L + R, press UP, UP, UP, B, DOWN.
Dual Guncons - hold L + R, press Y, X, UP, UP, UP.
Infinite health (human shields) - hold L + R, press B, Y, X, Y, B.
Stronger melee - hold L + R, press Y, X, X, X, LEFT.
Double melee damage - hold L + R, press X, X, UP, UP, B.
All enemies unarmed - hold L + R, press RIGHT, B, LEFT, X, Y.
Invisible Jack - hold L + R, press Y, Y, UP, UP, Y. Note that enemies can still see Jack, but you can't him (except the ball shadow