And that's not just me being undecided about this game. I think its own genre is also quite undecided. As mentioned by an earlier comment, the game sort of crossed between a shooter and an avoider. It's not a bad idea entirely, but it does seem that they take turns to dominate parts of the game. It's basically an avoider till you get to the bosses. Kind of like it hasn't made up its own mind yet what it wants to be.
The game is quite well made, albeit a little short. The obstacles were pretty straight forward and there was some good variation with the enemies.
I felt the gameplay was a little on the slow side with the movement. I was quite relieved when the game speed sped up nearing the end. Thats where the speed really needs to be to keep up the excitement level. But once the speed did go up though, the movements became quite inadequate because they were so slow, particularly the backward movement. I understand the slowness when the ship is moving forward, but come the boss battle at the very end, it was ridiculously slow moving that I couldn't avoid the boss charging towards me.
Pick up the game pace, and make the controls more responsive. Also, I think you can fully expand on the whole 'avoider/shooter' concept. Think of a way to completely blend the two instead of having one and then the other in different parts of the game. Like the first bit with all those moving wheels, why not just put enemies in there as well? Make that gun you've given more useful in the entire game, not just for the boss fights.
I do like the change of direction midway through the game. I think you should expand on that concept more.
Overall, not too bad. Not too exciting either, but I think you can really take this idea and beef it up a little with more enemies, more action.