The Penumbra universe was originally created by Swedish developer Frictional Games as a tech demo to test out the capabilities of their HPL engine. But due to an exceedingly positive reception of the tech demo, developer Frictional Games made many modifications to the original engine to support the 3D graphics used in Penumbra, and decided to turn it into a full-length product. The game is heavily influenced by H.P. Lovecraft (even naming the engine after him) in parts of the story and names of the characters. The game made its debut on March 30, 2007 by means of Digital Distribution, then later at retail on May 8th, 2007. It is now available through many services, such as the developer's own website, Gametap, and Steam, and is one of the few franchises with native support for Windows, Mac and Linux.
Penumbra is, at heart, a first person adventure game, with various elements in it. Most of the game is comprised of making your way through various creepy atmospheres to uncover the truth behind the mysterious story, and solving thought provoking puzzles. Penumbra takes advantage of Newton Game Dynamics to introduce physics based puzzles and combat. There is also a stealth element to the game, as it takes advantage of advanced artificial intelligence that responds realistically to things such as noises and light, making the player have to think and move strategically to not be killed.
Although there is combat, the game tends to heavily focus more on avoiding and running away from combat than facing it. The game is limited to a small set of melee weapons, including a pick axe, a crowbar, the characters fists, or anything around the character that can be used, since everything in the environment can be interacted with. The player can even do things like locking enemies in rooms, and depending on the room, use things such as poisonous gas to eliminate them. Basically, the gameplay is comprised of exploration, and collecting and interacting with objects to solve its various puzzles and mazes.
The Penumbra storyline puts the players in control of series protagonist Phillip, who is trying to solve the mystery that sprang forth from receiving a letter from his dead father. His adventure brings him to Greenland where everything starts to unfold and a world of horror opens up for the unsuspecting Phillip. The story spans two full-length games, Penumbra: Overture and Penumbra: Black Plague, with a second expansion Penumbra: Requiem , which ties loose ends in the story.