Submachine gun, miscellaneous items:
Press Triangle, X, Square, Circle, Triangle, Up during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect.

Sniper, miscellaneous items:
Press Triangle, X, Square, Circle, Triangle, Right during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect.

Rocket launcher, miscellaneous items:
Press Triangle, X, Square, Circle, Triangle, Left during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect.

Heavy machine gun, miscellaneous items: 
Press Triangle, X, Square, Circle, Triangle, Down during game play. A message 
will appear at the top of the screen to confirm correct code entry. Repeat the code 
to disable its effect.

Shotgun, miscellaneous items:
Press Triangle, X, Square, Circle(2), Up during game play. A message will appear 
at the top of the screen to confirm correct code entry. Repeat the code to disable 
its effect.

Nail gun:
Press Triangle, X, Square, Circle, X, Left during game play. A message will appear 
at the top of the screen to confirm correct code entry. Repeat the code to disable 
its effect.

Unlimited ammunition:
Press Triangle, X, Square, Circle, X, Right during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect.

Cycle through spawn points:
Press Triangle, X, Square, Circle, X, Up during game play. A message will appear 
at the top of the screen to confirm correct code entry. Repeat the code to disable 
its effect. 

Maximum charisma:
Press Triangle, X, Square, Circle, X, Down during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect.

Invisibility:
Press Triangle, X, Square, Circle(2), Left during game play. A message will appear 
at the top of the screen to confirm correct code entry. Repeat the code to disable 
its effect.

Slow motion:
Press Triangle, X, Square, Circle(2), Right during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect.

Fast motion:
Press Triangle, X, Square, Circle(2), Down during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect.

Flymo ragdolls:
Press Triangle, X, Square, Circle, Square, Up during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect.

Invincibility (PAL version):
Press Triangle, X, Square, Circle, Square, Right during game play. A message will 
appear at the top of the screen to confirm correct code entry. Repeat the code to 
disable its effect. 

Bonus level:
Successfully complete the game to unlock the Liberty Island level. 

Master Code:
On the pause menu, press X, TRIANGLE, CIRCLE, TRIANGLE, X, TRIANGLE, X, 
TRIANGLE, CIRCLE. 

Blind Enemies:
Press Triangle, X, Square, Circle(2), Left during game play. A message will appear 
at the top of the screen to confirm correct code entry. Repeat the code to disable 
its effect. You can walk up to enemy soldiers and attack them without being seen.

Unlock Liberty Island:
To unlock the extra stage, Liberty Island, just beat the game on any difficulty.