18 Wheeler: American Pro Trucker
Bonus parking levels:
Successfully complete each of the four parking levels to unlock
an additional parking level. Successfully complete the bonus
parking level to unlock a sixth parking level.
Hold X and press Start at the title screen. Keep X held until the
mode selection screen appears. Choose any mode to drive the
Nippon Maru truck.
Successfully complete the game with all five trucks (Asphalt
Cowboy, Stream Line, Long Horn, Highway Cat, and Nippon Maru).
Successfully complete arcade mode with all four characters to
unlock two bonus trailers in score attack mode, versus mode,
and arcade mode (if the Nippon Maru is selected).