Awesome game! The music is great, and the graphics and sound effects are so crisp. Really feels good to play. I especially like the trails for the ship thrusters, explosions, etc. Are those just customized Unity Particle System trails, or something else you made?
I like this use of the theme as a game mechanic, and I'm totally not biased since my game you played also has upgrades on death. :-)
One critique I would give is that I initially found myself wanting to use the brakes to carefully shoot at something, but using the brakes narrows the camera which makes it harder to see what I'm trying to shoot. Of course, I ended up using the brakes less and less anyways since standing still was too dangerous with lots of enemy ships on screen!