very cool idea, I had a few issues tho (and i don't mean this in a bad way, more of like a "if you want to continue the project you might think about.." way)
- it felt like no matter the size of the asteroid, they still stopped me in the same way, which would maybe be nicer if the impact on the player would be dependent on the size of the asteroid
- the red damage numbers when hitting a spaceship made it seem to me like it was wrong to do so, maybe it was just personal preference, but it took me a while to realize that those were the damage numbers and not my score
Overall, very cool concept with nice music and art