A new battle mode level (In the Gutter, Sea Sick, Blizzard Battle, 
and Lost at Sea) will be available for each world that is completed 
in Adventure mode. Alternatively, use a third party controller with 
a pause feature to stop game play. Then, repeatedly tap Start. A 
sound will confirm correct code entry. Note: For the Japanese 
version of the game, use a Joy Card 64 controller. Set the controller's 
slow switch to the "Hu" position at the title screen and wait for the 
sound that confirms correct code entry. Four new levels will be 
accessible in battle mode.