Simple but fun arcade-like experience, not hard to understand but a lot of room to 'git gud'
The only small nit-pick I have is that the rocks, especially the blue ones, can be a bit hard to see on the background. That combined with how quickly they fly can make avoiding them a bit annoying. But other than that I didn't have any real problems with the game.
Overall good job with the submission.
Also as someone who also uses Game Maker, the camera/parallax scrolling is really cleaver and makes it a lot more dynamic than it would otherwise be.