Unlock More Parking Levels:
Complete all four parking levels to unlock an additional parking level. Complete the 5th parking level to unlock a 6th parking level.
Unlock Nippon Maru:
Hold X and press Start at the title screen. Keep holding X until the mode selection screen appears. Choose any mode to drive the Nippon Maru truck. Alternately, successfully complete arcade mode with all four trucks.
Unlock Lizard Tail:
Complete the game with the 4 regular trucks and the Nippon Maru.
Unlock Trailers:
Complete arcade mode with all 4 characters to unlock two bonus trailers in score attack mode, versus mode, and arcade mode (if the Nippon Maru is selected).