Unlock Bonuses: Earn Cheats
Earn a 3-star rating on any level in order to unlock a bonus piece of artwork. As an added bonus, each piece of art has half of a code on it. Combine the left bonus' code with the right bonus' code to get the cheat. Cheats can be entered on the title menu.

Various Codes
The following codes have no effect until you complete the both levels with at a five star rank under the hardcore difficulty setting to unlock them. Each code has two parts, each of which are unlocked by a specific level (for example, at the end of level 1 and level 2 with at least a three star rank). When this is done, one half of a code will appear at the bottom of the image that is now unlocked in the "Bonus Features" menu. Once both halves (images) are unlocked, that specific code can now be activated in any level in the game.

Fully Equipped:
Press R1, R2, L1, L2, Down, Up, Left, Up at the main menu. Complete the Drunk Driving and Graveyard Shift levels to unlock this code.

Helium Hunters:
Press R1(2), Triangle, Circle, Square, L2, L1, Down at the main menu. Complete the Strapped for Cash and View Of Innocence levels to unlock this code.

Invisibility:
Press Square(3), Down, Square, Down, Circle, Up at the main menu. Complete the Trained To Kill and Border Patrol levels to unlock this code.

Monkey Skin:
Press Square(2), R2, Down, Triangle, Square, Circle, Down at the main menu. Complete the Press Coverage and Wrong Side Of The Tracks levels to unlock this code.

Piggsy Skin:
Press Up, Down, Left(2), R1, R2, L1(2) at the main menu. Complete the Key Personnel and Deliverance levels to unlock this code.

Rabbit Skin:
Press Left, R1(2), Triangle, R1(2), Square, L1 at the main menu. Complete the Kill The Rabbit and Divided They Fall levels to unlock this code.

Regenerate:
Press R2, Right, Circle, R2, L2, Down, Circle, Left at the main menu. Complete the Fueled By Hate and Grounds For Assault levels to unlock this code.

Runner:
Press R2(2), L1, R2, Left, Right, Left, Right at the main menu. Complete the Born Again and Doorway Into Hell levels to unlock this code.

Silence:
Press R1, L1, R2, L1, Right, Left(3) at the main menu. Complete the Road To Ruin and White Trash levels to unlock this code.

Super Punch:
Press L1, Triangle(3), Circle(3), R1 at the main menu. Complete the Mouth Of Madness and Doing Time levels to unlock this code.

Unlock Bonus Games
To unlock the bonus games, you have to earn three star ratings on groups of five levels. The games are unlocked thusly:

Hard as Nails: Get three stars on each of levels 1-5.
Brawl Game: Get three stars on each of levels 6-10.
Monkey See, Monkey Die!: Get three stars on each of levels 11-15.
Time 2 Die: Get three stars on each of levels 16-20.

Killing Your Enemys
Here is a quick tip on the best way to kill your enemy. First off, everyone should know how to snuff the enemey (you do this by quitely killing your enemey quickly). This is done by sneeking behind the enemy and holding L1 to target. Once your target/aim has gone white, hold it for longer til it turns red. This will provide a quicker more powerfull execution.