Look, I'm IMMENSELY biased here since I adore rhythm games (esp rhythm heaven), but man I loved this one! The audio design is incredible, especially the way that the various hit noises are balanced to give you solid feedback on how good your timing is, and the beatmaps are incredibly well-designed. Loved the use of the ZUN-style sketches for the intro and outro!
I enjoyed this one so much that, upon stumbling on the english settings, I ended up playing the whole thing again to read the story this time, and had just as much fun the second time. Seriously, if y'all end up making more rhythm game stuff, please let me know because I'm dying for more stuff with this level of polish. Superb work.