It fits the theme by changing either the shapes/colors/particles of the enemies with each wave and as you get further into the game it gets more confusing. For example the green circle with shield particles might be a red hexagon with bow particles by wave3 which makes you think its not the enemy it really is.
As for shooting issues i believe it should be fine cuz everyone that i've seen play it hasn't had any and also it doesnt seem like anyone else from the comments has had shooting issues, but also i doubt it's your pc bcs the game doesn't really need a powerfull pc to run it. It's something i would have to look into, as well as balance the game a little better
Thanks for the feedback! And also i really enjoyed the devlog! Keep up the great work!