Amnesia offers immersive puzzles to the player by creating interaction that comes natural to the player. When a door needs opened, the player must pull their mouse towards them to actually open the door, same goes for drawers as well. It is through these interactions that the player can feel as if they are actually manipulating these objects instead of just pointing and clicking like so many other puzzle games.
Much of the game is inspired by Lovecraftian horror wherein the player is constantly assaulted with their sanity being eroded as they try to regain their memories. Monster lurk within the game that are quite frightening and the whole game is sparsely lit with constant sounds surrounding them that could be eluding to their next encounter.
Sadly the core of the game is the puzzle aspect but they tend to be easily enough solved, which makes for a bit of a let down for players who are used to or looking for difficult gameplay.
Throughout the game the player is tasked with opening doors, rolling barrels, or pulling open drawers, this is done by using certain mouse motions to complete, so say for instance if one wants to open a drawer they need to not only click on it but hold the click while making a pulling motion with the mouse. It is through this realistic portrayal of interaction that allows one to feel immersed in the game environment.
Penumbra offers puzzles in a realistic setting where if one wants to get pas say some oil barrels, the obvious solution is that you can burn them. It is through using puzzles that ask for logical solutions that the game sets itself apart from many puzzle games where solving is not quite so logical.
As the game progresses the player ascends deeper and deeper into the characters madness that more and more is the users fault, or so the game makes one feel that way. There is a sense of dread as one explores as well and when combining these feelings one can't help but feel not only responsible for what is happening but also be frightened of it.
Each level is randomly generated, so each play session is fresh to the player making for a new experience each time played as to not become repetitive.
While it is by design there is no real purpose outlined in the game nor is there any tutorial that explains anything, it is up to the player to figure out how the game works. This can be frustrating for some players.