I like the music, but I don't really get the control.
Besides the arrow keys, is [Spacebar] used to shoot? And is the sector that keep rotating around you meant for aiming?
I was still able to "play" in the 1st level by kiting the mob around, smashing the Spacebar and collect some the monster drop. After I got the "Double" power, there seems to be some kind of projectiles that resemble bullets, but I don't know how to control them at all.
I did try looking at Settings to see if there is any key mapping, but found none.
Anw, the above critique is not meant to say this is bad. Just saying that a better intro could potentially make a better entry ramp. Then the rhythm and power-ups can make this really fun to play.