Shooting being tied to moving is a fun idea and the constantly rotating player fits well with the theme.
I found it difficult to time my shots. My bullets kept barely missing the enemies. Maybe power-ups or some kind of way to slow down the player's rotation?
If you decided to expand on this, the one button controls means this could be made into a mobile game quite easily. More enemy variety would be cool to see as well.
Nice job on the game!