Amnesia The Dark Descent Movie?

[JPPaperstacks]

H.P. Lovecraft's: The Necronomicon,
Dagon,
Cube is completely sideways and has a science fiction setting, but something is itching me to mention it.
The Tree of Life has some good Spanish plundering and trip scenes.
And so does Blueberry (Renegade). <---- AMAZING MOVIE.

Also, sorry for the bump.
Didn't realize until it was too late. :/

Cube is a real classic. Cube 2: Hypercube was also pretty interesting but inferior to the first one for sure. Since this topic seems to be more about good horror recommendations rather than creepy old castle horror movies (of which there are few) I'll list some genuinely scary ones:

In the Mouth of Madness
The Thing
The Evil Dead
Hellraiser
Jacob's Ladder

also check out the animated series Salad Fingers which is sure to freak the hell out of you.

Blueberry and The Tree of Life are in no way horror, but they have the same theme of insanity and spirituality-
(Unseen alien "entities" causing events to unfold in mysterious ways- Blueberry's is almost overwhelming.)
HELLRAISER: THE INFERNO IS BEASTLY. Thank you so much for reminding me.

Salad fingers will soil your pants for you, especially while in lesser state's of mind.