This is a great game! I really like how it looks, and it's clearly been optimized very well (although it does lag on the largest scale, that's to be expected). The main issues I found when playing have already been talked about by other people, but there are a couple other (minor) details I'd like to mention:
-It'd be nice for the videos to have skip buttons
-The stars in the background constantly flickering in and out can be kind of disconcerting
Other than those, the rest has already been addressed either in other comments or by you. Really solid. As I said before, the graphics feel very space-like. The audio fits very well for a game set in space. The overall ambiance is good, the only real thing weighing it down would be the small problems with the gameplay. With a little more time, I imagine that most, if not all the main issues could have been smoothed out easily.
Great game!