Super nice polish to the game; the sounds, animations, particles and intuitive diegetic menu all make the game feel like a fully fledged app already!
At first I found it pretty difficult when I got over round 10, but then I found a pretty cheesy way of getting all the asteroids by hovering the launchers just around the globe and blasting the asteroids miliseconds before impact. Although it was a ride to figure that out, once I did I kind of felt like I optimised the fun out of the game... haha.
I also thought it could be interesting to limit the amount of rockets players had, or have time between shots, to discourage a spray and pray... although that certainly was fun too.
And finally it could be cool to see a 360 assalut of comets, but I suppose that'd need to introduce other factors like sound to make players aware of where they were coming from.
Great little game! A bunch more levels and a few cosmetic variations and I could see this on the Quest store in no time.