Don't use unity's built in physics for platformers please. Also, make sure you add coyote time to your ground checks.

You took basically all of the fun things about asteroids and got rid of it, and the result is honestly just a crappy knock off. For starters, the controls are absolutely atrocious, why would you make 8 directional movement for an asteroids game is beyond me. I'm not sure if you're just new to game dev or what, but you want to use floating point numbers for the movement for smooth turning. There is also no juice whatsoever in the game, no sounds, no tweening, no animations, menus, any sort of visual or audible feedback not even a point system. These are the things that make playing games fun and rewarding for the player, I would look into the basics of game design philosophy it will really improve your skills.

controls feel pretty decent actually. Levels are complete with thought out gimmicks/design. But when starting new levels often the player character will get clipped into the environment