I enjoyed the filter you have on the game, it give it a very unique feeling that I just love. I enjoyed the variety of enemies and how I could tell them apart by color and weapon size. The screen shake is super satisfying as well. I saw you didn't create the music but it does fit perfectly with your game. The gameplay is good, I was able to win as the heavy and the light.
If you wanted to improve, the cursor on the menus isn't lined up to the center dot and instead is near the top, this confused me at first. Some sort of button to instantly start the next wave could be nice too. Some sort of score feature could be cool too, combining it with unlocking different units could give the game a really nice arcade vibe. Some sort of power-up to temporarily turn you into another class could be fun too.
Also, the game counts down as if there's one more wave after you win instead of just ending, not really an issue of any kind but something that could be nice to fix in a post-jam version. Also, enemies could get stuck on corners or between walls as a group and are super easy to kill when that happens.
Also, any reason why mute and unmute ended up being two different buttons?