I still have a steam copy, so I will be fine, but I have showed it to friends.
Much of it is that the game is uniquely buggy in a way which makes it utterly unpredictable, made more unsettling by the complete darkness and echoing sound design. I once spawned into a map with the satyr stuck in place but all I saw was its shadow projected across a distant wall and it looked like it was dancing. Deeply unsettling. Lots of stuff like that, being chased and opening a door into a brick wall, how the ends of a floor where you got the key were bizarre and impossible to predict what would happen, field of space, field of ants?
It felt like a game which knew it has rules to follow but wanted to get to you anyways, and you never knew when it was going to spring something on you. I haven't found almost any games quite like that feeling.