Wow!!
This game blew me away, i've rated about 20 so far and this is far and away my favorite.
I love the aesthetic, the gameplay, and the concept so much (i named my first dog after Laika and she recently passed </3)
I love that you can "melee" the enemies as well as shoot. If you were to continue developing this, i'd say add challenge rounds with many planes or asteroids but only those enemies, or rounds where you can't shoot, or rounds where you can't "melee" so to speak.
Great work!!