This game was initially released only in Japan and in Europe. It was later ported to the US PlayStation Store.
There is an option in-game that lets you place any physical CD into the PlayStation and the game generates obstacles to the music as if it was its own. To allow for this option, the game was designed to have a small file size so as to be loaded fully into the PlayStation's RAM, allowing the game disc to be switched out and an audio CD put in its place.