Get a gold medal rank on the indicated level to unlock the corresponding cheat in an apartment sub-menu. Note: You cannot progress in the game if any cheats are enabled.

Crazy Deaths: Lucky's Bar
Gun Splitters: Crack House
Invulnerability: All levels
No Reloads: Stark Towers
One Shot Kills: Ryker's Island
Unlimited Ammo: Pier 74 Revisited
Unlimited Slaughter: Takagi Building