I'm not sure how to describe this. I feel shaken by this game in a way standard horror doesn't really do. Perhaps it's that it finds horror in the ordinary and mundane, but improbable. The sort of thing that can just happen, with no rhyme or reason.
The storytelling here is top notch. The visuals stellar. Sound and music are used deftly to add to the tension, the dread.
My heart is still beating fast several minutes after playing this.