Change The Character
During gameplay you an press the select button and then highlight the Select button. Now enter:
L2, L1, L2, SQUARE, CIRCLE, SQUARE, L2, L2, L2, L2

Do not move your cursor, yet. You can hit the L2 button until you've selected your character.

One Shot One Kill
During gameplay you an press the select button and then highlight the Select button. Now enter:
L2, L1, L2, SQUARE, CIRCLE, SQUARE, L3, R3, CIRCLE, SQUARE.

You'll hear a sound if you entered the code correctly

Unlimited Health
During gameplay you an press the select button and then highlight the Select button. Now enter:

L2, L1, L2, SQUARE, CIRCLE SQUARE, R3, L3, R3, CIRCLE.

You'll hear a sound if you entered the code correctly

Extra Powerful Punches And Kicks
During gameplay you an press the select button and then highlight the Select button. Now enter:

L2, L1, L2, Square, Circle, Square, R3, L3, Circle, Square

You'll hear a sound if you entered the code correctly. Now when you punch and kick an enemy they'll go flyin'.

Itty Bitty Characters
During gameplay you an press the select button and then highlight the Select button. Now enter:

L2, L1, L2, SQUARE, CIRCLE, SQUARE, L3, R3, SQUARE, CIRCLE

You'll hear a sound if you entered the code correctly

Unlimited Phase Cloak
During gameplay you an press the select button and then highlight the Select button. Now enter:
L2, L1, L2, Square, Circle, Square, L1, R3, L2, L3

You'll hear a sound if you entered the code correctly. Now you can stay Invisible for as long as you want.

Big Head Mode
During gameplay you an press the select button and then highlight the Select button. Now enter:

L2, L1, L2, SQUARE, CIRCLE, SQUARE, START, SQUARE, CIRCLE, START.

You'll hear a sound if you entered the code correctly

Godly Guns
During gameplay you an press the select button and then highlight the Select button. Now enter:
L2, L1, L2, Square, Circle, Square, L2, L2, L1, L3

You'll hear a sound if you entered the code correctly. This code will give you Unlimited Ammo and you'll never have to reload.

Huge Characters
During gameplay you an press the select button and then highlight the Select button. Now enter:

L2, L1, L2, SQUARE, CIRCLE, SQUARE, R3, SQUARE, CIRCLE, L3.

You'll hear a sound if you entered the code correctly

Avoid Fall Damage
When you fall from high area you take damage. When you near the ground push L2 to do a flip. This will eliminate damage.

Hard Mode
During gameplay you an press the select button and then highlight the Select button. Now enter:
L2, L1, L2, SQUARE, CIRCLE, SQUARE, R3, L3, CIRCLE, SQUARE

You'll hear a sound if you entered the code correctly