This is really good, you nailed the fun factor in my opinion, which is always one of the best things you can do, and I think it's a great exploration of the theme. Even after I died ten or so times I really wanted to keep playing to see what it was like to get all the powerups and see if I could match or beat your high score. (Spoiler alert: ....um...no).
I love the music and the SFX, the first couple of times I died the screen breaking explosion and the Atari-like death SFX made me laugh out loud.
The visuals are obviously on the minimalistic side, but I think that probably made this a better experience because it was nice and readable.
Constructive Criticisms:
Some of the SFX were too high in the overall mix and were thus a bit harsh and unpleasant on the ears, specifically the default player firing sound and the clear screen powerup effect. Remember that human ears hear higher pitched sound better than lower pitched sounds, so sometimes you need to lower the higher pitched ones in the overall volume mix of your game so they don't overwhelm a listener's ears.
This one is more subjective, but I don't think I agree with the design choice of making the side of the screen deadly. I think there was plenty of challenge to be had with fighting, dodging and grabbing powerups, and it felt like one too many things to worry about.
Overall though, top notch submission, very well done!