Unlock the following bonuses by performing the corresponding tasks:
HOW TO UNLOCK
Boss Only mode
To unlock Boss Only mode, obtain the Mysterious Button from D'Artagnan on level 5 under the Normal or higher difficulty.
To unlock the Fear difficulty setting, obtain the terror medallion from one of the three black star enemies on level 4 under the Hard difficulty setting. Then, complete the game under the Hard difficulty setting.
To unlock the music room, find the music room key on level 6 under the Normal or higher difficulty setting.
To unlock the Planeriel difficulty setting, obtain the nightmare medallion from the Nightmare Of Legend enemy on level 3 under the Fear difficulty setting. Then, complete the game under the Fear difficulty setting.