It's a nice little concept, but it gets repetitive really fast. There's a lot of ways you could add some variety.
For example:
- adding power ups (increase strafe speed, get invincibility)
- making the asteroids speed more variable (currently it almost seems like they are all flying at the same speed; making some high speed asteroids could help)
- adding some vertical movement too, so maybe also adding sideways movement of the rocket
I like the graphics, especially the lighting.
Adding some ambient music would help a lot. Even just pasting in some random royalty music could help a lot.
Still, a cool experience!