This was really cool, and a very creative take on the theme. It took a little bit for me to understand how things work but once I got it it was really fun. The use of orbits is pretty clever. The one big thing I think could be better is that I think you should be able to angle your shot manually rather than having to time it. The element of timing would still be there with the orbit mechanic and that would make retrying similar shots less of a pain. One other little thing is that I think on levels that span more than a single screen, it should automatically scroll when you get to the checkpoint. I didn't realize there was more to the level and was confused at first. Aside from those things though this was really cool, nicely done.