Highlight a fighter on the character selection screen. Hold Circle + Square and press Start.

Highlight a fighter on the character selection screen. Hold Down + X + Circle and press Start.

Push Select(10) at the title screen. A chime will confirm correct code entry.

Push Right(10) at the title screen. A chime will confirm correct code entry.

Push Left(10) at the title screen. A chime will confirm correct code entry.

Complete the game four times to unlock the four hidden characters.