3600 round machine gun - At any level before the stage where you have to kill General Tatarin, go to the rebel base. Go in circles around it to find a machine gun that has 3600 rounds.
Blind enemies - While playing the game, press Y, A, B, X(2), Left. If you entered the code correctly, a message will appear at the top of the screen. You can walk up to enemy soldiers and attack them without being seen; however, your men cannot see enemies, and will not shoot them. Repeat the code to disable its effect.
Bonus level - Successfully complete the game on the Rebel or higher difficulty setting to unlock the Liberty Island level.
Cycle through spawn points - While playing the game, press Y, A, B, X, A, R. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Defeating General Tatarin - To easily kill General Tatarin on your first trip to Governors Island, sneak down to where you have to go right over all the barriers. Take out those troops and look for a wall that is shorter than the buildings beside it. Try to look over the barrier to see a basement entrance. Then, look for a window that has a light behind it. Enable the "Rocket launcher, miscellaneous items" code. Fire at the window and the "Killed Tatarin" message should appear. Then, run away quickly. Alternately, walk down the same way, but get on top of the crates. There will be a guardrail where the first fence segment ends. If you are lucky, you can jump to it, climb the rail, and find the door. You will fight various opponents and finally the General. If you enable the "Blind enemies" code, it will be a lot easier, and you can kill General Tatarin with any weapon.
Fast motion mode - While playing the game, press Y, A, B, X(2), Down. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Flymo ragdolls - While playing the game, press Y, A, B, X, B, R. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Hair length - While playing the game, notice that Chris' hair gets longer with every mission.
Heavy machine gun, miscellaneous items - While playing the game, press Y, A, B, X, Y, Down. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Hitman references - Play the level where you liberate the fire station. When you go to the railroad to blow the bridge, when you first get down there you will see a derailed boxcar with the IO logo and "47 UNITED". Additionally, play the level where you seize the police station. From where you start, go to the streets. On the one corner is a red, white, and blue diner with the name of "OG's". On top is a billboard for a men's suit designer, featuring 47.
Infinite ammunition - While playing the game, press Y, A, B, X, A, Right. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Invincibility (PAL version) - While playing the game, Y, A, B, X, B, Right. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Kill your own soldiers in Thin Ice mission - Your first objective is to destroy the ventilation shaft so that your troops can roll up inside. After you complete the objective, send one of your troops to the middle of the destroyed fans. Then, throw a grenade at them. Some will just duck and when the grenade explodes; they will fall down and die.
Level select - Successfully complete the game. Your cleared save game file will now be marked "All levels unlocked". Load it to choose any level to be played.
Maximum charisma - While playing the game, press Y, A, B, X, A, Down. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Nail gun - While playing the game, press Y, A, B, X, A, Left. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Police station weapons in Soviet Domination mission - After talking to the policeman at the end of the tunnel, crouch, then walk directly forward to the left of the wall. You will see an open door. Walk in it towards the underground parking garage. Near most police cars there will be a shotgun. Be careful, because there are enemies.
Programmer message in Liberty Island mission - At the end of the level, enter the head of the Statue of Liberty to see a programmer message in lights.
Returning to boat in Liberty Island mission - Once you kill General Tatarin, do not bother taking land back to your boat. Just jump into the water and swim there.
Rocket launcher, miscellaneous items - While playing the game, press Y, A, B, X, Y, Left. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Shotgun, miscellaneous items - While playing the game, press Y, A, B, X(2), R. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Slow-motion mode - While playing the game, press Y, A, B, X(2), Right. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Sniper, miscellaneous items - While playing the game, press Y, A, B, X, Y, Right. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.
Submachine gun, miscellaneous items - While playing the game, press Y, A, B, X, Y, R. If you entered the code correctly, a message will appear at the top of the screen. Repeat the code to disable its effect.