A+ material. The best designed an executed game I've played so far. Everything is near perfect for 48 hours of work.
Design within the theme is amazing, one star, one planet, one moon, one color, one button, and one objective. Nothing seemed out of place, and all the elements fit together.
The gameplay is awesome too. It ramps up from peaceful to frantic, and there's a bit of strategy to defending, since it's easier to hit things on the far side of the star, and exploding bullets mean you get benefits from letting stuff clump up, but it's risky because the chain explosions may not hit everything.
Then, there's the polish. Lots of little particles, simple sound effects when stuff explodes, a very nice difficulty ramp, and the amazing intro. Seriously, that intro sold the game to me before I even started playing.