This is Bunker: The Underground Game. You probably never heard of it but since you now have, you are one of the cool kids. Game takes place deep down in a forgotten Soviet bunker. You spend rest of your absurd adventure puzzling, mini gaming, pointing, clicking, hipstering, err humor-ing oh and escaping what is no doubt the weirdest...
Open the Steam client, login and locate the Games tab on the top menu. Click this and then select “Activate a Product on Steam…”
Enter your unique code that's displayed on the 'Orders' page of CDKeys.com and follow the prompts to activate.
Your game is now viewable in the “Library” tab and is available to download/install when you’re ready. You can find additional support for the Steam client here: https://help.steampowered.com/en/wizard/HelpWithSteam