OK (Mid-level) is a performance rating in the Rhythm Heaven series, depicting that the player did an average job clearing the game. This rank is required to pass a stage.This rank is provided as an in-between for the "Try Again" and "Superb" rating. This rank is normally recieved during ordinary play, or after the player has practiced a bit.
The OK rank has a subsidiary called "Just OK," which is midway between "OK" and "Superb." The player recieves a Just OK rank when they have fulfilled one or two Superb requirements, but not all three. This rank counts as an OK for all purposes.