This hits hard! Well written and well polished. The emotion of the story & music contrasted well with the frantic way I felt I needed to move & click avoid the monsters: like I was trying to outrun the decay of my mind.
I loved the decay mechanic: it felt really stressful and really motivated avoiding the monsters. It also looked cool with the pieces flying in and out, the camera adjusting, etc. I also thought you introduced and mechanics of decay and avoiding the creatures well -- it was just unforgiving enough to teach the mechanic quickly.