Complete the game on Normal.
Successfully complete the game on the easy difficulty setting to unlock Art Gallery 1 and the Cabal guns.
Successfully complete the game on the normal difficulty setting to unlock the .50 Desert Eagle and the hard difficulty setting.
Successfully complete the game on the hard difficulty setting to unlock the Molotov cocktail and the expert difficulty setting.
Successfully complete the game on the expert difficulty setting to unlock the rocket launcher and Cabal rifle.
Successfully complete instant action mode on the easy difficulty setting to unlock the Cabal SMG and the Art Gallery 2.
Successfully complete instant action mode on the normal difficulty setting to unlock Extra Adrenaline.
Successfully complete instant action mode on the hard difficulty setting to unlock Extra Health and the expert difficulty setting.
Successfully complete instant action mode on the expert difficulty setting to unlock Extra Ammo.
Pause the game and press X(2), Up(3), Down(4). If you entered the code correctly, you will hear the sound of a scream.
Complete instant action mode on Hard.
Complete the game on Expert.
Complete the game on Hard.
Complete the game on the Easy difficulty setting.
Complete instant action mode on Easy.
Complete instant action mode on Normal.
Complete instant action mode on Expert.
Complete the game or instant action mode on Hard.