HL2 Ravenhom had a decent mood to it, but wasnt nowhere near scary. I liked the tone of it, indeed, but i was a walking army in that, so i was rather confident in what would happen.
The scariest moments in video games are in Thief series. People often mention Theif 3 and Shalebridge Cradle, indeed a masterfully crafted level. But It's topped on many levels by Thief 2, in several places (the pre-finale meeting with the pagan and their living tree monstruosities come to mind, but a lot of other moments are very high in tension and fear). The reason why Thief 2 was superior is, the expert mode gameplay, in which it was forbidden to kill anyone (except during the very finale, for obvious reasons), and in some places even knocking people unconscious was forbidden. That meant, pure stealth, creative use of your ears and brains..
In a way Amnesia recreates that by barring you from using weapons. For once you can use another part of your brain, rather than the primal reptilian part that pulls the trigger on your comfy AK47. Yeah it's satisfying making insta puree out of zombie heads, but it's nowhere scary. Amnesia is a Lovecraft fan wet dream. You're in the clothes of a Lovecraft characters, living one of his demented stories. The game oozes personality, the backstory is a very obvious nod to the Cthulhu myth, the victorian era characters and places really add up, why would we need any weapon, we win by the force of our grey matter, not by using boomsticks for once, that's what still differentiates us from primates.