Don't be thrown off by the fact this game plays about 10 years older than its release date. It does have some clunk to it, but for the most part, it is dated in a positive way taking the aspects from older generations of horror games that fans of the genre appreciate.
It pretty much ticks all the boxes a survival horror fan might look for with the exception of combat. It has a deeply immersive atmosphere powered by a darkly captivating world, an eternal darkness-like sanity system that warps POV, and a fantastic soundtrack. The puzzles are creative and challenging without being frustrating for the most part. I also appreciate that some of them have multiple solutions including working the game's physics system into the puzzles. The level design is solid with a nice combination of linearity and non-linearity despite the confined spaces.
However, I do believe it is held back slightly on a few fronts. While, I am fine with minimal combat, they should have been more creative with the "action" around that idea. More sequences like the aquatic (leaving this intentionally vague to avoid spoilers) one early in the game could have elevated my rating. The variety is left lacking due to the designers not being imaginative enough with these interactions. Additionally, the ending, while satisfying for my playthrough on a narrative level, was anti-climactic in my opinion.
Overall, it's a damn good game that deserves the cult-classic label it has. While it is not near the top of the genre for me (LOU, Evil Within, Multiple REs, etc. Are better), it will most likely enter into the back end of my top 100 games after I've thought it over.