Push start to pause the game and then give the follewing combinations to activate the cheats.

Big guns:

square ( 4 times ), circle ( 2 times )

Missile crossbow:

right, right, left, left, L2, L2, R2, R2, circle, circle, square, square

Missile sniper:

square, left, right, L2, R2, right, square, R2, R2, L2, left, left

Explosive crossbow:

left, right, right, left, square, circle, L2, R2, square, circle, left, right

Explosive sniper:

L2, R2, right, right, left, left, right, right, R2, L2, square, circle

One hit kills:

circle, left, right, right, left, circle, L2, R2, circle, square, square

Ulimited ammo:

square, circle, square, circle, square, circle, square, circle, left, square, circle, square, circle, square

Unlimited TOC:

circle, circle, square, square, left, right, right, left, L2, R2, L2

Unlimited spycam:

left, left, right, right, R2, R2, L2, L2, square, square, circle, circle

50% damage:

square, square, circle, circle, left, left, right, right, circle, circle, square, square

No damage done by bullets:

left, right, right, left, square, circle, circle, square

Skip level:

L2, square, L2, circle, L2, left, L2, right, L2, R2, R2, square, R2, circle, R2, left, R2, right, square

complete bank level:

R2, L2, square, circle, left, R2, left, left, square, circle, square

complete carmen level:

R2, L2, right, left, left, L2, R2, square ( x3), R2

complete Forsythe level:

L2, L2, left, left, left, L2, R2, square, R2, square, R2

complete installation K level:

R2, L2, square, square, left, L2, L2, square, square, L1, square

complete La Casa level:

R2, L2, right, left, left, L2, R2, square ( x3 ), R2

complete Magyar level:

R2, circle, circle, left, left, L2, R2, right, square, right, right

complete Mod level:

R2, L2, right, R2, left, circle, R2, circle, right, right, left

complete museum level:

L2, L2, right ( x3 ), L2, R2, square, R2, square, R2

complete Reliance level:

R2, L2, right, left, R2, L2, right, square, circle, square, circle

complete Silo level:

R2, L2, right, left, left, L2, circle, R2, square ( x3 )

complete training level:

left, right, right, left, circle, square, R2, L2, circle, circle, square