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, highlight the "Battle" option on the main menu, then repeatedly tap Start. If you entered the code correctly, you will hear a sound. 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. Then, four new levels will be accessible in battle mode.