Alternate Costumes
At the character selection screen, highlight a fighter. Then, hold Circle + Square and press Start.

Deformed Characters
At the title screen, press Select 10 times. If you entered the code correctly, you will hear a chime.

Hidden Characters
Beat the game four times to unlock the four hidden characters.

Paper Cut-Out Style Characters
At the title screen, press Right 10 times. If you entered the code correctly, you will hear a chime.

Small Characters
At the character selection screen, highlight a fighter. Then, hold Down + X + Circle and press Start.

Stick Figure Characters
At the title screen, press Left 10 times. If you entered the code correctly, you will hear a chime.