Penumbra

"You know... Clarence... that's not a bad handle - I am something of a guardian angel."
- Clarence

Not too long ago I finished Penumbra Overture and Penumbra Black Plague. I did try out the expansion - Reqiuem - as well, but grew tired of it when I found out there was only puzzles in it and almost no suspense or atmosphere or even much story to it.
                                             (Spoiler alert)
However Overture and Black Plague are great games that chilled me to the bone, almost as well as Amnesia did, much thanks to the great atmosphere and involving gameplay. There were a lot of memorable moments in both games, but the one that stands out the most has to be in Black Plague, where you as the player reaches and enters the research room where the apparant only survivor and your only friend -Amabel Swanson- is located. The protagonist has himself gotten infected and therefore recieved a voice in his head calling itself Clarence, being the manifestation of the virus.
Inside the research room you get locked inside with one of the infected personnel and you have to act fast. You lure your enemy under a crane carrying a box and drops it onto him. Afterwards you come to your senses and as it turns out you were only hallucinating, because of Clarence, and on the floor next to the box lies Amabel, dead by your own hand.
This was quite a shocking part and this was the part where I knew this was one of the scariest games I have ever played.

Penumbra © Frictional Games