Eleusis is a game which PewDiePie played from March 6, 2013 to March 17, 2013.
Eleusis is a horror RPG Mystery 3D First-Person Indie game by Nocturnal Works. It is also named after a town in Greece with deep historical roots. The game might be named after that, as the events in the game are related to Greek mythology. More on Eleusis.
This is a highly interactive 3D game, with similarities to Amnesia: The Dark Descent. PewDiePie goes about his usual routine of talking and naming inanimate objects, like he always does in Amnesia example: Will, a wheel which PewDiePie carries around and occasionally tosses into space. Several characters from Amnesia also appear like Jennifer and the lamp which is used in almost all Amnesia games.