Nice submission!
The star visuals / shader in the main menu looked really good! I liked the background during the game as well.
I liked that I can use mouse for spaceship movement - I don't like keyboard only movement in games like this.
What I would change / I noticed:
- The collision detection was a bit strange. I'm not sure if I collided with invisible asteroids or the collision shape for the ship/asteroid was a bit off.
- For submenus like the tutorial menu the small X at the corner is hard to notice. I pressed ESC because I didn't see it the first time, then pressing ESC closed the game. I think you should put a BACK button below the tutorial text.
- It was a really good idea to give outlines for the asteroids! It made them easier to notice / register for my eyes. I think the spaceship should have a bit thicker outlines as well. It's visible enough, but it would look better with bolder outlines.
Overall a good submission, keep it up! :)