This game, despite having simple gameplay, is quite fun to try and get a high score on. After quite a few attempts, I got a high score of 132. I don't think there's any difficulty scaling, but it sure does get more tense as your score increases, as you now have a lot to lose. I think the borderless arena is a fun mechanic that prevents corner-camping. It's satisfying to blast a large group of enemies, to then immediately fire in the other direction to avoid the enemies on the other side.

A remark: the fixed window size is pretty annoying, as clicking out of the game is way too easy with this game being mouse-controlled. I had to minimize all my apps including the game's console to be able to play.

I think it's impressive and cool that you made the game without any engine, just a renderer. That, too, fits the theme, but I think the game already fit the theme really well. Now I think that shotgunning insects in real life would just be 'It's stupid and it doesn't work'... admittedly, I never tried it.