At the Press Start screen, press Up, Left, Right, X, Circle, Square. You will hear a sound to confirm it.

For all the heavy metal vehicles, press L1, R1, L1, Square, R1, Up at the title screen. If done right a chime should go off.

At the Press Start screen, press X, Up, Triangle, Down, R1, L1. You will hear a sound to confirm it.

At the Press Start screen, press Left, Triangle, R1, Circle, L1, Down. You will hear a sound to confirm it.

At the Press Start screen, press Right, Square, Left, Circle, Up, X. You will hear a sound to confirm it.