haha, normally Im not into those "Bullet Hell" games, but actuelly like this one and a cool idea to mix music in that way.
I just played the demo short in thier homepage, actuelly I must tryoit how the "Droid Escape" perform in the game, but its in Flac, so I must convert it (but first tommorow).
So there is a actuelly a demo on thier homepage in flash...... But cool idea and nice done. of course only bosses, but elsewise its would not work.
PS. I should also checkout Arsanal too (that DS game).