I was hooked by the visual style of your game, I think it should be completely black and white then the game will look sick (in my opinion)) (UPD: Or at least without such player particles). The music is also good. The theme and ZERO UI are 100% complete.
You should rework the controls and perhaps remove the shield as a core mechanic. By the way, its rotation works very poorly and I had to stand still and shoot at the boss from afar because of this LOL.
Now your game is more of a foundation. I think that if you continue to develop the game, go beyond the concept of protecting the star and killing the boss and make something like an exploratory action game in space, it will turn out great!