Cleared the game with all characters (Arrange mode only).
You have to clear the game with all 3 characters (Asagi, Ageha, Tateha). Continues are allowed so this is an easy one.
Modes able to unlock this (confirmed): Arrange
Modes unable to unlock this (supposed): all other modes
* Changing setting in OPTION -> Game Config disables all achievements.
* Using Restart from pause menu disables all achievements in that play.