Penumbra (series)

Penumbra is the name of a video game series by developer Frictional Games, published by Lexicon Entertainment and Paradox Interactive. The games use the HPL Engine, initially developed as a tech demo. Penumbra is notable for its horror styling and for allowing advanced physical interaction with the game environment.

Besides the original tech demo, the series comprises:
 * Penumbra: Overture - Windows, Mac OS X, Linux (2007)
 * Penumbra: Black Plague - Windows, Mac OS X, Linux (2008)
 * Penumbra: Requiem, an expansion to Penumbra: Black Plague - Windows, Mac OS X, Linux (2008)