All songs:
Select arcade mode, then highlight "Hard" at the difficulty selection screen. Press
Right(3), select the "Hard" option, and begin game play. 

Character and arrow selection:
Select arcade mode, then press the Analog-stick in any direction at the difficulty
selection screen.

Additional game options:
Hold B while selecting the arcade mode option at the title screen to unlock options for
"Vs.", "Single Play", "Couple", and "Double".

Hidden mode option:
Select arcade mode, then choose any difficulty setting. Press the Analog-stick in any
direction, then press Up, Down, Up, Down, Up, Down, Up, Down.

Mirror mode option:
Select arcade mode, then choose any difficulty setting. Press the Analog-stick in any
direction, then press Left, Right, Left, Right, Left, Right, Left, Right.

Little mode option:
Select arcade mode, then choose any difficulty setting. Press the Analog-stick in any
direction, then press Left, Down, Right, Down, Left, Down, Right, Down, Up.