I really like the art style of your ships; they remind me a lot of old school elite.
The concept of having all ships shoot on the beat is really cool. I think you could definitely create a really interesting bullet hell shooter with this mechanic.
I found the controls a bit unintuitive but after playing it for a bit I realized it was mostly because the ship would move past my cursor and cause the ship to turn, but that would probably be a quick fix by max the direction relative to the screen center instead of the ship.