Really Awesome.
One of the few games of this sort that I actually enjoyed the flying part more than the upgrading part (learn to fly is the only other), which is the way it should be. The proportions of everything are very well balanced - amount of enemies and upgrades to dead space, and how much each upgrade helps and costs. The only thing that annoyed me was that if I flew into an enemy at the wrong angle (trying to turn away from it), it would knock me about a quarter of the total sky's height downwards, and it happened a lot. I wish the engine had a higher acceleration rate upwards from a fall, and that hull upgrades would keep the ship from rotating as much upon collisions.