This is really neat! I see it's been a while since it was published/updated but I figure I'd throw some feedback anyway since it's a demo?
- It got reallyyyy laggy near the end, like, 2fps level of laggy. I'm on firefox for the record
- I feel like radioactive meteors may need some rethinking, they were helpful right at the end but when you first unlock them, they make a cloud after being defeated but most of the time you're also getting rid of all of the other asteroids around them, making the cloud not do much for you.
- It also escalated really quickly near the end there, but I'm guessing that's due to you wanting to make the demo have a satisfying end XD It's still pretty linear feeling in general though and that didn't help
This is a cool demo though! Good luck with the rest of it!