Zombified:

B,Y,X,A,X,A'
annette333

Hold down the shoulder buttons while you are on the CompStat/Map screen before pushing the following buttons:

Code Effect

B,X,B,X All Music
A, A, X, A, A, A Double Damage
X, X, Y, X, Y, X Get a Million Dollars
Y,A,B,X New Puma Outfit In Puma Store
Y, A, Y, A, Y, Y Super Cop
B, X, A, A, Y, B Ultra Easy Mode
B, X, A, X, X, Y Unlimited Ammo
B, X, A, X, A, B Unlimited Endurance
Y, A, A, X, A, X Unlock Redman Gone Wild Mini Game

Unlockable  -  Puma Shoes Outfit Collect all 10 pairs of Puma Shoes then visit the Puma Shoe Shop to get the Outfit
Redman Gone Wild Mini-Game Complete the Game 100% and after you get a call from Redman go to his location to unlock this mini-game on the main menu.

Fights open:  Hold L + R and press X(2), B(2), X

Street Races open:  Hold L + R and press Y(2), A(2), Y

Better upgrades  -  As your rank gets better (5 being the worse, and 1 being best), you can buy better upgrades for your character at the Police Department Armory, such as better zoom for your guns, or a more slow-mo dive. You can also purchase new guns to use. The guns will be in the trunk of your police car that you get from the garage.

Easy money  -  Walk in front of a car and press Back. The driver will get out. Walk up to the person and press Back again to write them a ticket and summon them to court. You will get $10 each time this is done, but also one Bad Cop point.

Get cops to stop shooting you  -  Sometimes when you are in street clothes and shoot at someone in front of a cop, the cop will start shooting at you. To get them to stop, turn towards them and press Back to flash your badge at them. They should then stop shooting at you.

Get Money Fast Without Cheating  -  To get money fast with out cheating all you need to do is go to a car dealership. Once you are inside frisk everybody there (not the manager or the people who work there). Everybody in a car dealership has something bad. You then turn the evidence you got from the people to either the police station or at the swap shop place. If you go to the police station you can pick the money up with you pay check.

Ghetto city  -  At the CompStat/Map screen, hold L + R and press A, X, A, Y(3).

Non-fatal shots  -  When arresting people without killing them, enter Aim mode by clicking Right Analog-stick. Put your sight over either their arm or leg, wait for it to turn blue, then shoot. They will fall to the ground, and you can then arrest them. This is useful for increasing your Good Cop rank.

Reload stun gun  -  Commandeer any police cruiser, then open the trunk to reload your stun gun. This can be done repeatedly whenever the gun is low or empty.

Vehicle ranks  -  Achieve the indicated rank to have the corresponding vehicle available in the police garage:

Detective Rank 1: 6.5L V8 Custom SUV
Detective Rank 2: 5.4L SC V8 Coupe
Detective Rank 3: 2.5L L4 Sedan
Detective Rank 4: 6.0L V8 Coupe
Detective Rank 5: 3.5L V6 Sedan

Weapon and ability ranks  -  Achieve the indicated rank to have the corresponding weapons and abilities available in the police armory:

Detective Rank 1: 5.56mm Carbine, 7.62 Auto Sniper, Flashbang, Slo-Mo Dirve x2
Detective Rank 2: .45 Special, Tactical Shotgun, 5.56mm Bullpup AR, Sledge Hammer, Precision Aim Assist
Detective Rank 3: 4.6 MM PDW, Assault Rifle, Tranquilizer, Sunt Baton, Zoom 4x
Detective Rank 4: Stun Gun, 9MM SMG, Standard Shotgun, Slo-Mo Dive

Wrong subway map  -  When you go into the subway, walk from the stairs down to the other end of the platform. There is a wall, and on the wall is a subway map. If you look close at the map you can see that this is not the NYC subway map; it is actually the map of the Boston, MA public transit system, the MBTA. The words are not there, but the shape of the lines, and the colors are 100% accurate to Boston.

Zombie mode  -  At the CompStat/Map screen, hold L + R and press B, Y, X, A, X, A. Marcus will have no head, arms, or legs, with blood appearing from the stumps. Repeat the code to only have his torso appear.