Unlock the following modes by performing the corresponding tasks:
MODE - HOW TO UNLOCK
Stage mode - Beat a stage in Arcade mode on Normal difficulty to unlock it at the "Extra" menu. You can then replay that stage whenever desired.
Endless mode - Beat Arcade mode and all five stages in Stage mode to unlock Endless mode. In this mode, there are no Bosses, with the stages cycling endlessly.
Extra mode - Beat Arcade mode to unlock Extra mode after Arcade mode is selected again. In Extra mode, the difficulty level is increased.