https://store.steampowered.com/app/1769320/Athanasy
Deep beneath the surface of the dead Earth, the City, the last refuge of humanity, hides. Engineering genius and efforts of all mankind; a giant structure of steel, concrete, and biopolymers. It keeps the remnants of civilization one step away from total extinction.

INSTRUCTION FOR ACTIVATION:

1. You must download and install Steam http://steampowered.com/download/SteamInstall.msi
2. Log in to your account or register a new one.
3. Go to the "My Games" section and select "Activate via Steam ..." and enter the key received after payment.
4. After activation, the game will appear in the list of games (Library) and you can download it