Not going to lie, the first thing that came to my mind was this game from Vimlark: https://vimlark.itch.io/orbiting-defense
Nothing wrong with using an existing idea, that's how all games are made now a days in some shape or form. :D It looks a while for things to spawn so at first I though things were broken when suddenlythings started to appear which is probably my only nitpick. I feel that I did not have good visibility into what was coming next and had to react last minute. Maybe if something flashed in the direction things were coming or if I could zoom out the camera a little more by pressing a button that be nice