When you complete Training with the Silent Assassin rating this lethal paper weapon made from 6mm ultra dense, hand forged Musashi cardboard will become available. This melee weapon is used like a sword and has the ability to kill enemies with one hit and throw them long distances.
Unlock Level Select: To be able to choose what level you want to play in the game go to the 'Main' menu and press Square, Triangle, Circle, Left, Up, Right, L2, R2.
Unlock Level Skip with a Silent Assassin Rank and Special Weapons: During gameplay when a level is about to begin press R2, L2, Up, Down, X, L3, Circle, X, Circle, X.
Unlock ALL Weapons in Training Level: This sneaky little code will unlock ALL the weapons in the game which are at the weapons storage area. What you have to do is start the Training level and enter the 'Level Skip' code so you complete it with a 'Silent Assassin' rank. Select the Training level again and the weapons will ALL be unlocked.
Second Chance when Killed: To get this reprieve you have to quickly get 4 head shots when the screen turns black and white briefly when you have been killed. If you manage to do this you will continue playing the game but with hardly any health.
Unlock Bonus Weapons: Complete the the following missions with a 'Silent Assassin' rank to unlock the indicated weapon.
Unlock CZ 2000 Dual Pistols: Complete Mission 1 with a 'Silent Assassin' rank.
Unlock Micro Uzi Dual Submachine Guns: Complete Mission 2 with a 'Silent Assassin' rank.
Unlock Silverballer Silenced Dual Pistols: Complete Mission 3 with a 'Silent Assassin' rank.
Unlock Magnum 500 Dual Pistols: Complete Mission 4 with a 'Silent Assassin' rank.
Unlock Sawed-Off Shotgun Dual: Complete Mission 5 with a 'Silent Assassin' rank.
Unlock M4 Carbine Silenced Assault Rifle: Complete Mission 6 with a 'Silent Assassin' rank.
Unlock SG220 .S Dual Pistols: Complete Mission 7 with a 'Silent Assassin' rank.
Unlock MP5 Silenced Submachine Gun: Complete Mission 8 with a 'Silent Assassin' rank.
Unlock AK 74 Silenced Assault Rifle: Complete Mission 9 with a 'Silent Assassin' rank.
Unlock GK 17 Dual Pistols: Complete Mission 10 with a 'Silent Assassin' rank.
Unlock Micro Uzi Silenced Dual Submachine Guns: Complete Mission 11 with a 'Silent Assassin' rank.
Unlock PGM Silenced Sniper Rifle: Complete Mission 12 with a 'Silent Assassin' rank.
First of all go to the main menu then click training and once you are in the level put in the silent assasin cheat R2,L2,UP,DOWN,X,L3,O,X,O,X you will need to type it in fast and it may take a few trys , but once you have done it correctly it will come up the ranks skip that then it will say you have unlocked a bonus weapon.Save it and then in training you will have all the weapons , and in a real mission such as asylum aftermath when you get to select your weapons at the very top it will say tube take it with you and it will give you more starting ammo and more syringes !!. ENJOY!! By progamerkevin.
Okay this isn't really a cheat but I figured out how to get the mini gun. Go to the Wang Fou mission and go to Lee Hongs mansion. On the top floor there is a desk and on the desk is a key card. The key card unlocks the door in the asylum that the crazy is in that has the mini gun. Pick up the key card from Lee Hongs desk and then do the level skip cheat. Then go to the asylum(you don't have to epuip the key card at the beginning it is automatically equiped for you). Go to the door and kill the guy with the mini gun and take it. Then do the level skip cheat again and save your game. Now you have the mini gun.