For a small mini game it's decent.
Gonna just do a brief summary of what I thought
Graphics: graphically for what this game is it's decent/good, I like the use of orange and the graphic used gives the game an Asteroids feel, I enjoyed the look of it immensely but next time maybe you could use more colors to brighten it up a bit.
Sound: I do have a few bones to pick with the SFX, it's annoying that every time I get hit that the Wilhelm scream blares out, it doesn't fir the game at all, maybe you could use a different sound like a ship crashing effect, also the looping on the games music is weird at time, sometimes it stops dead and starts the next track, maybe you should make the music one track throughout the game as the stop in music breaks the flow of game play.
AI: I also have a problem with the game enemy's when they start to speed into handfuls a time from all directions, ultimately giving me not enough time to react and getting hit, coupled with that scream causing me to get hit more, pretty much just instantly ending the game, so that could be doing with some improvement.
Overall it's solid but the AI, Music/SFX could do with a bit of tweaking, It could become really addictive if your sort out those problems, and maybe add some Medal API so that getting scores feels rewarding I guess (personal opinion, not necessary), solid job but could do with some tweaking 3/5.