Maybe I'm just getting old, but this game seriously strained my eyes. The darkness of the environs combined with the in-built mouse acceleration making my viewpoint go wild made me feel ill. Once I had to start jumping across the floating Green Pickles of Destiny, I felt cold and clammy and had to actually stop playing.
I'd highly suggest some accessibility options for people, letting folks be able to control brightness, contrast, and mouse acceleration/sensitivity.