It's clear from looking through these reviews that this is a rather divisive game. Praised greatly by most - including the "editorial reviews" (which always seem especially weighty from their prominence in games' entry pages) - there's a significant minority of reviewers who don't like it, including one or two who really hate it. A smaller minority sit somewhere in the middle, liking it well enough, but not greatly so.
I find myself in that last group. I certainly don't dislike the game. But if it hadn't appeared on almost every "must-play" list, and if it weren't by a renowned author of IF, and if it didn't have all those glowing testimonials, and if it were just an obscure game I'd happened upon by chance, I wouldn't think it anything exceptional. Of course it's hard to say - perhaps under those circumstances I'd be more impressed by it. After all, when something is praised this much, it has a high expectation to live up to. And besides, when you're told repeatedly that something is deeply creepy and you can expect an experience of terrifying psychological horror, little short of being trapped in a vault with Edgar Allan Poe is going to impress.
So all that said, I thought it was a good game. It's a good idea well implemented. The writing is excellent. I liked "A broad mirror tries to make the place seem twice its size; it halfway works" - very droll. The implementation is mostly good - as others have noted, the idea of having sub-locations within the single location is effective. There were some oversights though - "go to kitchen", for example, doesn't work (you need to "go into kitchen" or "enter kitchen"). (Spoiler - click to show)Also, there's no "shower drain" object at all to interact with, even though it's specifically mentioned in the to-do list. I don't have a problem with the fact that the game railroads you through its narrative - that's not the kind of game I mostly enjoy, but it can still be effective, and once I'd worked out how to progress, I rather liked almost sitting back and allowing the narrative to take its course.
I don't think I experienced the creepy psychological horror that others report. Either I'm deficient in something or being so prepared for it immunised me. So the actual activity of playing it, while fine, wasn't the deep emotional experience that others clearly find it to be. But at the same time, I suspect that the imagery of this game will prove memorable. And even in a game where the player has very little choice, making these happen *to the player* rather than to a character in a conventional story over whom one has no control at all does add to their power.
So that's my small contribution to the mountain of commentary on this game. It's very short, it's straightforward to play, it's memorable. I wouldn't call it greater than plenty of less celebrated works that I've played. But perhaps to some extent it's a victim of its own success.