After playing the game probably 10-20 hours by now, both just for fun and to get footage for a video, my main gripes would be that the character controller is definitely odd and quite uncomfortable to use, and the lack of mouse sensitivity or FOV options are rough for quality of life - the FOV quite subtly gives the game a sort of nausea-inducing feeling in addition to the character controller.
Then, on top of that, the lighting being so extreme makes it a lot to... take in when you're playing.
I suspect some of these changes are related to the way the character controller is affected by the various armor pieces you can get which can be activated/deactivated to give bonuses to your movement.
I would imagine there was an earlier character controller that was a bit more intuitive and then they had to create a new one that was able to receive all these bonuses to various aspects of it, and creating a first person character controller from scratch is quite a frustrating and complex task. I don't blame them but I'd love to see a new version one day that uses a revamped character controller and has FOV and mouse sensitivity options.