To activate these codes, enter them while in the "Extras" Menu. You can then select them from the "Cheats" menu.
Code                    Effect
Up, Up, Up, Black, Black, Black, Up	Extreme Ragdoll
White, Right, B, Down, R, Back	Hippy Blood
Left, Right, Up, Down, click Left Analog-stick, press X	Infinite health
Back, R, L, Back, click Right Analog-stick, L	Infinite Supplies
X, X, X, B, B, B, Up, Down	Low Gravity Ragdoll


Unlockables
Unlockable Cheats/Modes

After completing one full game, all of these should be unlocked to you
Unlockable              How to Unlock
All weapons and upgradesComplete the game. Instead of starting a new game, use the Level Select cheat and start on the first level to keep everything you unlocked
Extreme Ragdoll         Complete the game on any difficulty, start a new game, enter the Options menu, select Cheats, this should now be activated
Hippy Blood: Changes blood into colorful flowers	Complete the game on any difficulty, start a new game, enter the Options menu, select Cheats, this should now be activated
Level select            Successfully complete a level to unlock it at the Cheats menu
Low Gravity Ragdoll: Enemies fly away when killed	Complete the game on any difficulty, start a new game, enter the Options menu, select Cheats, this should now be activated
Massacre Mode           Complete the game on any difficulty setting to unlock the Massacre difficulty setting