Free to keep when you claim to your Steam account before 12 Nov @ 8:00 AM. Note: free games don't drop cards.
Also available for free @ GOG until 12 Nov @ 6:00 AM. (Claim button is on the homepage - scroll down to see it.)
About the game:
SteamWorld Dig 2 takes you on a platform mining adventure forged in Metroidvania flames. When an old trading town is struck by mysterious earthquakes, it’s up to a lone steambot and her unlikely companion to uncover what trembling terrors lie beneath.
addlicense asf s/652120