Loving this so far! It's sucked me right in, I could see losing myself in it for a few hours if I'm not careful ;)
I did notice when I open the game menu there doesn't seem to be a way to close it again. It opens with escape, and I'd expect to be able to close it again with that, but it doesn't work. This makes it not possible to change settings like inverting the camera controls.
The reason I was exploring the settings in the first place was because I find the camera controls a little too sensitive, and I find myself wishing I could increase/reduce perspective with a control such as the mouse wheel or other. I'm often trapped in a corner or behind a wall, and would love to have more control when orienting myself in the game world.
All in all, fantastic work! I love it!