the 4 hidden achievements

[Ryverwynd]

Can anyone tell me what they are the are the only ones left i need

[Cirnopoly]

Recital:
Play the piano with the Fairy familiar equipped.

Deja Vu:
Go to the room underneath OD and use high jump under OD's chair until he bounces to the ceiling. Do this up to 7 times to also unlock 2 hidden treasure chests in the room.

Army of the Night:
Clear the game and watch the credits until the very end.

Usurper:
Kill Gebel AFTER getting the Zangetsuto from Zangetsu.
This will result into a bad ending and a GAME OVER afterwards.
* This is a different ending than killing Gebel BEFORE getting the Zangetsuto.

Overlord:
Clear all the other achievements.

[Ryverwynd]

thank you

[Silvershadow]

Thank you for reminding me of Army of the Night ... i skipped credits and wanted to watch them later but forgot about it *facepalm*