Level Codes:
While playing the specified level, pause the game and enter the following:

Bank Level Completed 
White, Black, X, Y, Left, White, Left, Left, X, Y, X 

Carmen Level Completed 
White, Black, Right, Left, Left, Black, White, X, X, X, White 

Forsythe Level Completed 
Black, Black, Right, Right, Right, Black, White, X, White, X, White 

Installation K Level Completed
White, Black, X, X, Left, Black, Black, X, X, L1, X 

La Casa Level Completed 
White, Black, Right, Left, Left, Black, White, X, X, X, White 

Magyar Level Completed 
White, Y, Y, Left, Left, Black, White, Right, X, Right, Right 

Mod Level Completed 
White, Black, Right, White, Left, Y, White, Y, Right, Right, Left 

Museum Level Completed 
Black, Black, Right, Right, Right, Black, White, X, White, X, White 

Reliance Level Completed 
White, Black, Right, Left, White, Black, Right, X, Y, X, Y 

Silo Level Completed 
White, Black, Right, Left, Left, Black, Y, White, X, X, X 

Training Level Completed 
Left, Right, Right, Left, Y, X, White, Black, Y, Y, X 

Pause the game then enter the following:

Big Feet
Right, Right, Right, Left, Right, Left, Right, Left, Left, Left 

Big Feet
X, X, X, X, Y, Y, Y 

Explosive Crossbow
Left, Right, Right, Left, X, Y, Black, White, X, Y, Left, 
Right 

Explosive Sniper 
Black, White, RIght, Right, Left, Left, Right, Right, White, Black, X, Y 

Half Damage 
X, X, Y, Y, Left, Left, Right, Right, Y, Y, X, X 

Level Skip 
Black, X, Black, Y, Black, Left, Black, Right, Black, White, White, X, White, Y, White, Left, White, Right, X 

Missile Crossbow
Right, Right, Left, Left, Black, Black, White, White, Y, Y, 
X, X 

Missile Sniper
X, Left, Right, Black, White, Right, X, White, White, Black, Left, Left 

One Hit Kill 
Left, Right, Right, Left, X, Y, Y, X No Bullet Damage 
Y, Left, Right, Right, Left, Y, Black, White, Y, X, X, X 

Skeleton Mode
L,L,L,R,L,R,L,R,R,R 

Unlimited Bullets 
X, Y, X, Y, X, Y, X, Y, Left, Y, X, Y, X, Y, X, Y, X 

Unlimited Life
Left, Right, Right, Left, Left, Right, Right, Left, Left, Right, Right, Left, X, X 

Unlimited Spy Cam
Left, Left, Right, Right, White, White, BLack, Black, X, X, Y, Y 

Unlimited TOC
Y, Y, X, X, Left, Right, Right, Left, Black, White, Black