There are two secret stages in beat mania 2nd remix. They are Rave 2nd remix and hard tekno. It's simple just go to arcade and when you pick expert hold the select buttom. While holding the select buttom just push the cicrle buttom and pick either classic for rave 2nd remix or techno for hard teckno. Rave would come up at the last stage and hard teckno would come up at the third stage.