From Wiki
The game casts the player in the role of Daniel, who awakens in a dark castle with little or no memories about himself or his past. All that he can remember is his name and that something is hunting him.
The game's story seems to be, at least in part, inspired by the short story The Outsider. This makes sense when considering the frequent homages the developers make to the author H.P. Lovecraft and his works. Even the engine which powers all Frictional Games's titles, the HPL Engine and the HPL2 Engine, bears the aforementioned author's initials.
In a similar vein to the developer's previous games, Amnesia is an exploration-based adventure game played from a first-person perspective. The player has no access to weapons, and they must use their wits to avoid or hide from enemies. The game also retains the physical object interaction used in Penumbra, allowing for advanced physics based puzzles.
I just got the game yesterday, holy stuff this beats the penumbra series by a long shot, it yet again pits you against a hostile environment with no means to protect yourself, even the darkness is your enemy, if you stay in the shadows for to long your sanity drains, and even though it's only the characters sanity draining you yourself feel yourself going crazy because of the sound thats made. One new thing that was been added are random events, sometimes you can go into a room with no enemies, sometimes a deformed zombie thing will burst in and you'll have to hide in a closet, overall and awesome game.
Also, you'll have to have some dedication to play this, sometimes you'll only figure out how to continue by getting killed and be given a hint of something you'd never think of. Not only that but getting oil for your lamp is a total bitch so a lot of the time you'll be relying on tinder boxes or running in the dark (VERY DARK THIS TIME AROUND) with your sanity draining.
