Awesome stuff. I actually accidentally spoiled myself whilst playing since I was looking through the comments for help in getting my sense of smell back, because I was having trouble understanding the walkthrough.
I knew that there was something creepy that was likely watching me in the top left corner of the screen, and still jumped out of my skin upon actually getting to see the observer. A really cool concept.
I only took off half a star since I wish the story was a bit richer, with more explanation of who or what the Observer is, and for a bit of convoluted-ness when it comes to the controls. (I was stuck because I had already tried to use the string on the snail, but not the snail on the string, so I just assumed that wasn't the solution to the problem.)