Fun game. I liked the spin mechanic and how you control the player with the mouse. Bosses are good.
The game seemed a bit loud when it first started. Might be nice to offer a slider for master sound and start it low. Also, I'm not sure if you did this or not, but normalizing your audio would also help. You can get Audacity for free and then run the music and sfx through the normalize tool to bring them all in line with each other.