I beat this. It was about 5-7 hours, depending on how long you take to read emails, story, solve puzzles, and how much time you spend dying. It's good, but it's very "janky," with a lot of minor bugs that can sometimes lead to frustration as well as some places that oddly lack polish, especially in the animations.
The best part of the game is the atmosphere. It is generally really really good, but the voice acting can probably be pretty detrimental for some people. I'd say it's perfectly fine about 80% of the time, but sometimes lines are delivered in ways that are distracting. For example, at one point, you briefly witness some ungodly horror, the likes of which have never been seen before by any living, normal person. In response, your character yells "what was that?!" in a confused, but mostly unconcerned tone. I started laughing when it happened, but if no dialogue were there, it would have been a genuinely very creepy moment.
While the atmosphere is usually good, the horror can be a mixed bag. Some of it is really good. Some of it just isn't scary. And, unfortunately, a bit too much of it is jump-scare oriented. These scares don't really stick with you after the fact, they're just surprising, so you gasp and jump.
The story is somewhere between complex & good and nonsensical. There are a lot of things that are well set up, and the story has pretty good pacing, with things always ramping up, to the point of it sometimes really surprising me. However, there are a lot of minor plot holes, inconsistencies, and lackluster moments. The worst example of this occurred for me when the identity of a mysterious character is revealed. It's intended to be shocking and come as a revelation, but I immediately knew who this character was at the very first hint of it hours beforehand. It was such a non-surprising reveal, I was really confused as to why the game was acting like it was so shocking and dramatic that I thought there must've been more to it, like it being a lie or something.
Like I said, it's overall a good game, and I'd recommend buying it, even at its base price since it's relatively inexpensive and I think it's good to support creative works like this. There's a lot of nice moments to be had, and I think that no matter how many issues someone may have with the game, you can't really dislike it. It's not ripping you off or lying to you and it really just wants to provide a good experience.