To use these cheats, you must first beat the game. In addition, you also must also unlock each of the cheats. Refer to the Unlock Trophies/Enable Cheats List to see how to do it.

Enable Cheats: CIRCLE, SQUARE, TRIANGLE, X, L1, L1, LEFT, LEFT
Gain All Weapons: SQUARE, X, CIRCLE, X, UP, DOWN, UP, DOWN
Improve Edges: L1, L1, CIRCLE, CIRCLE, DOWN, DOWN, UP, DOWN
Max Ammo: RIGHT, RIGHT, RIGHT, RIGHT, UP, DOWN, UP, DOWN
Max Health: TRIANGLE, TRIANGLE, CIRCLE, CIRCLE, SQUARE, L1, SQUARE, R1
Mega Melee Damage: DOWN, DOWN, R1, R1, UP, X, UP, CIRCLE
Monster Spawning On/Off: SQUARE, SQUARE, CIRCLE, CIRCLE, TRIANGLE, L1, L1
No Conviction Cost for Edges: L2, UP, X, UP, SQUARE, DOWN, DOWN
Tougher Monsters: SQUARE, SQUARE, TRIANGLE, SQUARE, L2, L2, UP, DOWN
Unlimited Ammo: X, TRIANGLE, CIRCLE, SQUARE, TRIANGLE, UP, DOWN, DOWN
Unlimited Life: RIGHT, RIGHT, RIGHT, X, UP, TRIANGLE, UP, SQUARE