Extra Chapter:

If you clear the chapters in order, you'll unlock a hidden final chapter.

 

 

Harder difficulties and weapons:

After beating the game with certain criteria, new modes, and weapons shall be unlocked.
 

Unlockable                                        How to unlock

Hard Mode                                          Beat Normal Mode.

Normal Mode                                      Beat Easy Mode

Unlock Cleavers                                 Beat Hard Mode in under 60 minutes

Unlock Katana                                   Beat Normal Mode in under 45 minutes

Unlock Mace                                      Beat Easy Mode in under 30 minutes.

Unlock New Background                    Beat Super Hard Mode.

Beat Hard Mode.                               Very Hard Mode

 

Sound Test:

This can be done during the second quest of the game, the first one in which you can have Princess Sakura as an ally. In the overworld, to the east of the Town of Inns (the first town), and south near the shoreline, there is a shop selling Eggplants for $50. Normally, you are supposed to go back to the Town of Inns and speak with the monster in the center of the town to turn it back into a human. However, if you buy an Eggplant, and then use it through the item menu, you will access a sound test mode. Use the D-Pad to shift through the music, the A Button to play the music, and the B Button to exit the mode.