This is for the original Penumbra tech demo. For the Penumbra series, see Penumbra: Overture, Penumbra: Black Plague, and Penumbra: Requiem.
Frictional Games
Frictional Games
Release date
July 4, 2006
Microsoft Windows, macOS, Linux

Penumbra is a tech demo made by Frictional Games to show off the power of the HPL engine, released on July 4, 2006 for free. It can be downloaded off of the Frictional Games website.


The Penumbra series is based on Frictional Games' earlier game "Penumbra", a short tech demo meant to demonstrate the capabilities of the company's HPL Engine. The developers admitted to making significant modifications of the original engine to accommodate the 3D graphics in this game,

"The engine is built from an engine created when making a thesis job which resulted in the platform game Energetic. Before moving into the 3rd dimension I made some cleanup of the engine (which was quite rushed in some places) and started to add a base for 3D rendering. I would not say that the original 2D engine was modified to add 3D, but rather a 3D layer was added so all of the 2D stuff is still there. It is still possible to make a 2D tile game using our engine."

While not initially intended to be a commercial product, Penumbra was received exceedingly well, and Frictional decided to develop it into a full-length game.


Penumbra was made after Thomas Grip's first project, Unbirth. Unbirth was gonna be a Silent Hill/Resident Evil type of horror game with less violence, made on a commercial engine that a friend of his, Pierre Renaux, was developing and was letting him use for free, with the condition that the game was gonna be the engine's tech demo.

However, after multiple updates to the engine that broke Unbirth, Thomas decided to put Unbirth on hiatus and try to a new game on an engine of his own with a new team, this game ended up becoming Penumbra, and eventually Thomas completely abandoned Unbirth in favor of extending Penumbra and moving onto new games.


In Penumbra, the player, assuming the role of a nameless protagonist, finds himself in an underground base on Greenland, searching for his lost father. It's an adventure horror game, free from classic first person shooter elements, with an emphasis on puzzle solving and exploring. Constantly on your toes you will never know what to expect, with no weapons; how do you protect yourself?

Unused ContentEdit

See: Penumbra/Unused content


  • The theme of the tech demo is remixed for the credits music in Penumbra: Overture.
  • In the storage area where the roach appears, there's a locked door that leads to a bathroom. When near that door, one can hear low breathing coming from inside. The file is called "horror_breath1" located in "sounds\horror" of the game's install folder. It is isn't clear why this is here, although it could be a reference to an easter egg no one has found yet.
  • The most common book that appears in the tech demo, a book on human anatomy misspelled "Human Anathomy", bears the figure from the iconic Leonardo da Vinci drawing Vitruvian Man on it's cover. Intentional or not, Leonardo da Vinci is an important figure in the Penumbra series; as revealed in Penumbra: Black Plague, he and his student Francesco Melzi were the ones who laid the foundations for and the founder of the Archaic, respectively.
  • There is an unused texture for the spine of the Necronomicon, originally intended to appear as part of a row of non-interactable books on a bookshelf, an obvious reference to H.P. Lovecraft who was the main inspiration for the game.
  • The key model has the fictional brand "Troy Tough" on it. This is a reference to modeler and texture artist Troy Gusler.
    • There is a similar reference to Gusler in Penumbra: Black Plague; the lever model has the copyright "Yort Industries" on it, Yort being Troy backwards.
  • The writing on the overworld note texture is readable, and reads out "This note is note for you. It is for me! 15 433 2X"


Pre-release Edit

Screenshots Edit

External links Edit