I'm super surprised how well you pulled this off, because I'll be honest, I thought it was maybe not the best idea when I first saw it. I like that your enemy design uses the FOV and that it's not just a gimmick. I wish I could've gotten further, but I couldn't get past the third wave.
Probably the biggest issue I had was equating directions on screen with how I was moving in the world. I think there's probably some sort of UI you could add that could be enabled/disabled that could help a lot with this. Maybe some sort of grid or placing images of the WASD keys over the corresponding areas of the screen.
At any rate, this is a batshit concept that you have executed very well. Hats off to you folks.