this game has an amazing list of songs, and i love the ost outside of the vocaloid songs here too. its fun to play with the loids though im confused as to why gumi is excluded from that? the ui and overall aesthetic is great, and omg!! pinocchio-p made the theme and outfit for that one module for this game!! there's even an 8bit version of the song!!!! yeah.
if you are at all interested in the project diva series or rhythm games in general: PLEASE PLAY THIS GAME AS EARLY AS POSSIBLE. it has an insane amount of love put into it and is easily the best rhythm game at delivering extra content and fun little pet mechanics, but sadly it's just too easy minus a couple tracks. if this is your first rhythm game you will fall in love with it, but once you've played enough of the genre there's very little reason to go back to it.