Great game, quite fun. I found the movement very smooth and loved the model of the spaceship used. But there is room for improvement.
As others have mentioned, the asteroids need some more contrast compared to everything else, and I think the background could stand to be less busy. Right now there's tons of little white stars flying around which are decorative, but altogether a bit distracting, so toning those down might be nice.
Additionally, the game needs more of a challenge. Right now I'm not finding it all that difficult to get past asteroid cloud after asteroid cloud. There's many ways you could do this, maybe with a variety of challenging items/enemies, increased speed, etc. One way I thought of that might be interesting is if instead of flying through some asteroids, then getting empty space, what if it was just constant asteroids? Could be fun, perhaps.
Something small I noticed was that the music restarts every time the level restarts. This is small but makes a pretty big difference. It can be fixed using the singleton instance model and using DontDestroyOnLoad() with your audio manager.If you're interested, Brackeys has a great tutorial on how to do this in just a few minutes.
Overall, fantastic job and very clean. Quite fun to play.