A solid game ... that desperately needs more.
This is a pretty game. It's simple, follows a tried and true game concept, it looks good, sounds good, and plays reasonably well. That said, it's dull.
It's a little too simple. Both in concept and gameplay.
I barely took any damage and didn't even lose a ship until the fourth level boss. By that time I was fairly bored with the game. The levels are all very similar and some more variety would spice this up a lot. On the next level I decided to lose intentionally and I found it was tedious and almost difficult to do so.
I may have missed something, but the gun upgrade didn't seem to work a lot of the time. Perhaps after a while, you are fully upgraded? A little more information about that would have been helpful.
I think the speed of the game is far too slow. If it were faster, that would give it more replay value. As it stands, I don't think I'll play it again.
It was a good effort, but it's just not very interesting.