Firstly I'm real impresssed this ran so well in browser. Nice one!
I really enjoyed the vibe of this, and managed to beat it alright. Reminded me of Slender back in the day. Obviously, as a sound guy I feel that sound would elevate the experience a lot. I didn't feel all that stressed, and I rate sound could add to that feeling. Think the entity could have some very creepy sound design ala Annihilation. Well done!