Tenebra is a monotone psychological horror game relying on your observation skills as all you can do is move, crouch, and look around. But that doesn't make the game any less creepy! This game doesn't really use the backlight that your PC monitor has, so make sure you try this game when the sun went down or is hiding behind thick clouds.

In Tenebra you have to find a serial killer by using the clues around you while walking around in the dark.

Tenebra is definitely worth a try, especially since it is a free-to-play game based on the Source Engine. To be able to try Tenebra you will have to:

Install SDK Base 2013 Singleplayer by going to Tools >> Select and Install the SDK

Download Tenebra by clicking here.

Extract the game into your sourcemods folder >> ..Program Files/Steam/steamapps/sourcemods

Restart Steam

The developers also recommended to keep the "HDR" setting that you can find in the advanced video settings on "Full".

Oh, one more tip.. There is no use button.

When you're done, feel free to rate Tenebra in their designated gamepage on ScaredToPlay!