The game is too laggy, Don't know what is happening, maybe it is because I played on Lutris but I don't think so as I saw that you stated with high DPI it could cause too much sensitivity. But here it's not only sensitivity it's also laggy.
Si basically I couldn't test it much. I liked the visual aspect of the level I think it was really good, and it looks like you could "assemble" and so upgrade your weapon but it was so laggy not even when rotating camera but just when moving my character with arrow keys that I couldn't survive a wave.
Test my game and comment it for feeback plz!