Recently, inspired by Noah Gervais' excellent analysis of Clive Barker's games, I've started playing Undying.
There are so many things I love about this game! The atmosphere, the story, the environment design, the journal entries... But at the same time, unfortunately, I'm not really into, uh, actually playing it. It's a very hard game, and I have to reload and retry a LOT. It's survival horror, so resources (like ammo or health kits) are scarce. And I grow tired of it quickly. I usually play at most 20-30 minutes in one go, then take a day-long break..
Also, so far it feels very linear in a way. Of course, the maps are complex, there are many doors and corridors... but ever so often when you want to go through a door where you are not supposed to go at the given moment of the game, it is jammed ("it won't budge," the protagonist announces). And there is lot of backtracking. E.g. early on in the game you have to go out to the garden through a door in the west wing of the building. When you get there, you learn that the key is in the east wing, so you have to backtrack, then explore the east wing. Ugh. Am I spoiled by tabletop RPGs? :)