At the Press Start screen, hold L1 + R1, then enter the codes.
Cheat Mode – Circle, Square, Up, Circle, Triangle, Down
All Characters – Circle, Triangle, Circle, Triangle, Circle, Down
All Sleds – Circle, Square, Circle, Square, Circle, Left
All Tracks – Circle, Left, Circle, Right, Circle, Up
Hover Sled – Circle, Triangle, Square, Circle, Triangle, Right
