Unlock Cheats:
During gameplay press START and enter the following codes: 

Half Damage: 
X, X, Y, Y, Left, Left, Right, Right, Y, Y, X, X. 

Bulletproof: 
Left, Right, Right, Left, X, Y, Y, X. 

Invincibility: 
Left, Right, Right, Left, Left, Right, Right, Left, Left, Right, Right, Left, X, X. 

Infinite Ammo: 
X, Y, X, Y, X, Y, X, Y, Left, Y, X, Y, X, Y, X, Y, X. 

One-Shot Kills: 
Y, Left, Right, Right, Left, Y, Black, White, Y, X, X. 

M7 Turned Frag Launcher: 
Black, White, Right, Right, Left, Left, Right, Right, White, Black, X, Y. 

Crossbow Turned Frag Launcher: 
Left, Right, Right, Left, X, Y, Black, White, X, Y, Left, Right. 

Big Weapons: 
X, X, X, X, Y, Y, Y. 

Big Feet: 
Right, Right, Right, Left, Right, Left, Right, Left, Left, Left. 

Skip Cutscene: 
Black, X, Black, Y, Black, Left, Black, Right, Black, White, White, X, White, Y, White, Left, White, Right, X. 

Watch End Cinema: 
White, Black, X, X, Left, Black, Black, X, X, White, X.