Everything a bullet hell game should be. Including the insane difficulty :) They're theoretically possible but still incredibly challenging, and that's perfect.
This is amazing. As it is right now, I would pay money for this. The only things I can think of to improve it would be: A larger grid so that I could make songs several minutes long, more instruments (a piano sound, a trumpet sound, a flute sound), using the names of the instruments instead of numbers and being able to export songs as an mp3 file or something. As I said, though, it's already "I would pay money for this" quality. Favorited and 5 stars.
 "Pause Ahead"){kind=icon}
 "Reactance 2"){kind=icon}
 "Crystal Story"){kind=icon}
 "Song Builder(BETA)"){kind=icon}