"Penumbra: Overture is the first in a series of episodic games developed by Swedish developer Frictional Games. It was originally intended as the first episode of a trilogy. With the announcement of the second episode, Penumbra: Black Plague, it was stated that the second game would be the final chapter. However, an expansion has been released since then: Penumbra: Requiem, giving the series a third chapter, although not continuing the story in any way. (...)
Although Frictional Games describes Penumbra: Overture as a first-person adventure, the game blends the genres of survival horror, first-person shooter, and adventure. The use of Newton Game Dynamics emphasizes physics-based puzzles as well as physics-based combat. The game also takes advantage of advanced artificial intelligence to respond realistically to noises and light, creating stealth-based gameplay.
There are no firearms in the game, so during combat the player is limited to improvised melee fighting with a pickaxe, or throwing objects at attacking creatures. The game is designed to emphasize stealth and avoidance over direct conflict. For example, Philip can close doors behind him to temporarily hold off attacking enemies.
The game's main focus is on exploration and classic adventure game object interaction: examining and collecting objects and using them to solve puzzles."
Source: Wikipedia, "Penumbra:_Overture," available under the CC-BY-SA License.