Doorways: The Underworld (Steam key/Region free).

http://store.steampowered.com/app/311250/
Doorways: The Underworld is a first person horror adventure, featuring a complex story and deep atmosphere. It will challenge you with its fast-paced gameplay and breathtaking visuals and sounds, so prepare to immerse yourself in a terrifying psychological experience.

The Underworld is the third chapter of Doorways. It is not necessary to have the first chapters in order to play this game. But we recommend to do so for a better understand of the story.

You´re playing as Thomas Foster, a special agent who must track a missing psychopath. Who is she? What is this place and how did you get here?

These are just some of the questions that you must answer during your journey...
Key Features
Horrifying exploration adventure with an immersive atmosphere
Ingenious puzzles as well as challenges that put your reflexes at test
Inspired voice acting by Sam A. Mowry (the voice of Alexander in Amnesia: The Dark Descent)
Replayability through many secret places
Full Controller support
Native Oculus Rift support