Unlock Cheat Menu
At the Main Menu hold Left Trigger Right Trigger R L and press White Black Black White White Black.
To get infinite painkillers you have to press start during a game then press white, white, black, A, B, X, Y, Y ,Y, R, and then right by your health bar it will say 100.
Weapon & Refill Codes
At the main menu screen the screen where you can select new game, resume game, ect. hold down both of the thumbsticks and both triggers L & R AT THE SAME TIME. Then, while holding the thumbsticks down and holding both triggers down press White, Black, Black, White, White, Black. This code will work if you do it right.
This will open an additional menu at the bottom of the screen. Once you get into the cheat code screen, you can select two things; all weapons and refills. An explanation for each is described in the game when you highlight it in the menu.
In order to use the cheats, you must first start a game. Then, once your new game has started press the back button on the controller to access the main menu. Then go into the cheat menu and activate the codes by pressing the A button on the cheat you wish to activate.