Where do you see the GOG key? I bought it and don't see it.
I'll just copy my post from another thread. Talking about the Retro City Rampage site:
"There's a link in the Game Features that goes to either the Steam version
or the GOG version
I wish the GOG one was more obvious and not hidden in small text below the purchase window."
Also, if you bought the wrong version, email Humble Bundle support, give them your transaction ID, and they should be able to give you a refund so you can buy the version you intended.