View the Bomber Prince
Complete ten stages in quest mode, then enter the practice room. Then, place all characters in the hallway and return to the practice room. Now the Bomber Prince will appear approximately 50% of the time.
Quicker game
At the title screen, hold Circle and press Start to begin the game without the special effect sequence.
Extra levels
Beat quest mode once. Then, the "Honey" and "Cotetsu" levels will become selectable.