It’s like I say, one can’t lose with a wave-based arcade game. :)
As it’s been mentioned already, having such a slow turning speed was a bit frustrating. It would have also been fun to have the opportunity to upgrade the ship at the end of each wave. Some background space music would have helped enter the mood, even if it were a simple loop.
But overall it felt like a solid experience. The graphics are the best part of it: clean, legible, and thematically fitting.