Infinite Ammo
Equip the main gun you want to use for infinite ammo. Then pick up another gun to switch your main gun to your right hand. When your ammunition supply is almost depleted in your main gun, holster your weapons, then fire the gun quickly into the air by pressing "R2" and "R1." The clip will automatically reload as your character completely holsters his guns. Keep note that this trick will only work when you have guns in each hand, and when you are on open ended missions.
Car Codes
These codes will modify the car size, weight, and even upgrades.
Every driving upgrade unlocked - "Left," "Right," "Left," "Right," and "X."
Large car (be inside it when you enter this code) - "Down," "Down," "Down," and "X."
Small vehicle - "Up," "Up," "Up," then "X."
Lower car mass - "Down," "Down," "Down," then "X."
Bigger car mass - "Up," "Up," "Up," and "X."
Note: You must punch in these codes at the Map Screen.
Impound Garage
The game relies heavily on the cars you drive, providing better speed, armor, and endurance during the harder missions. One simple code will unlock every possible car in the game, so you can drive the best vehicle during your missions.
Unlock every impound garage car - "Up," "Right," "Down," "Left," "Up," and "X."
Just like the car codes, this must be input at the Map Screen.