Wow, I am impressed.
The whole game itself was quite good for a flash game. The sound was crisp, the graphics and movement great, and controls worked very well. I loved how the long shooting star like enemy things moved and appeared with the music. It was very beautiful. It made me feel the rhythm of the game, rather than just play a game. The framerate would drop on high quality, exactly what you said at the beginning, but it ran fine at low quality or downloaded so it's fine. I only wish there were more songs than one. But for the one song, it played excellently. Cheers