Very interesting.
This was a very unique game. Kind of got the Bejeweled thing going on there, but with moving planets. And I like how the planets within your circle can explode when it hits the line. Simple concept, but you know, this gets right hard when you progress in the game (well, no $hit.. lol), and it gets harder to try and get perfect (no $hit.. again lol). Also, I like the idea of the comets. Although the "challenge rounds" aren't that hard.
You should add like a time limit challenge, or a "don't miss a planet or you fail" type of thing. But anyway, a greate game. At least it's a great way to test your "circling speed", but that skill would be useless in the real world lol. Oh well.. :P But anyway, awsome game. I'd love to see a sequel in the future (hopefully..). 10/10! :)