Click here, login, scroll down and claim. Don't fret if it doesn't work right away. A few site issues with everyone rushing in (people seem to be having more success using GOG Galaxy app).
Description: from Steam
It is the year 2034. Beneath the ruins of post-apocalyptic Moscow, in the tunnels of the Metro, the remnants of mankind are besieged by deadly threats from outside – and within. Mutants stalk the catacombs beneath the desolate surface, and hunt amidst the poisoned skies above.
But rather than stand united, the station-cities of the Metro are locked in a struggle for the ultimate power, a doomsday device from the military vaults of D6. A civil war is stirring that could wipe humanity from the face of the earth forever. As Artyom, burdened by guilt but driven by hope, you hold the key to our survival – the last light in our darkest hour…
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Only two days remaining in the Epic Games 15 day giveaway as well
Torchlight II & Jurassic World Evolution.