I can just agree with the others :) the shooting is fun and I really liked the idea with the different gravity levels. It also was a good idea to give the game a little story and also name the planets (which reminded me of star fox/metroid actually. Great!).
But I also must agree with the commenter below who points to the misleading guiding coin in the second stage :( that was mean.
Btw the music fits the game quite well and gives a fitting vibe, but the loop is a little short in my opinion