Level Select: At main menu enter: R2, L2, UP, DOWN, SQUARE, TRIANGLE, CIRCLE
All Weapons: While playing a game enter: R2, L2, UP, DOWN, X, UP, SQUARE, X
Invincibilty: Enter this code while playing a game, R2, L2, UP, DOWN, X, R2, L2, R1, L1
Enter these codes during gameplay: Slow motion - R2, L2, Up , DOWN, X, UP, L2
Full Heal - R2, L2, UP, DOWN, X, UP, DOWN
Punch Mode - R2, L2, UP, DOWN, X, UP, UP
Gravity - R2, L2, UP, DOWN, X, L2, L2
Lethal Charge - R2, L2, UP, DOWN, X, R1, R1
Bomb Mode - R2, L2, UP, DOWN, X, UP, L1
Megaforce - R2, L2, UP, DOWN, X, R2,R2 (restart level to remove effects)
Nailgun Mode - R2, L2, UP, DOWN, X, L1, L1
Level Menu (activated at main menu) - R2, L2, UP, DOWN, SQUARE, TRIANGLE, CIRCLE
During gameplay, press R2, L2, UP, DOWN, X, L3, CIRCLE, X, CIRCLE, X.
In the Motorcade Interception Level, one of the mission objectives is to spare the UN guards. You can kill them from behind with the Wire without being penalized.
On some missions where you have to get passed a door you need your lock pick but it takes hours so start to pick then go to your menu and when you go back its done
Earn a Silent Assasin ranking on the St. Petersburg missions. Once you complete "Invitation to a Party", you unlock the M4.
To unlock the sawed-off, beat any two missions with a Silent Assassin ranking.
To unlock the Silenced Ballers, get a Silent Assassin ranking on any mission.