High Quality Content by WIKIPEDIA articles! Amnesia: The Dark Descent (previously known as Lux Tenebras or Unknown) is a survival horror video game by Frictional Games, who previously developed the Penumbra series. Released for Windows, Mac OS X, and Linux platforms, the game features an unarmed protagonist exploring a dark and foreboding castle, while avoiding monsters and other obstructions as well as solving puzzles. The game was critically well received, earning two awards from the Independent Games Festival and numerous positive reviews.