2) If you're willing to trade a game of the same value why not just go buy Dying Light yourself?
Geez, he's from Germany! If you still don't understand, than you should probably stop asking question like this. O.o
So he's trying to circumvent German law... essentially doing something illegal?
Or how about if he's that limited in what he can buy perhaps don't say "A game of your choice for the same price"?
Maybe a third option is that it's GOG... he can say he's from the U.S. & just have it payed for via a means that doesn't show on his personal history. Besides are they really checking his personal history that closely? Not like they'll be able to tell if he's downloading it or not; all they'll see is he's connecting to GOG servers which is what he does when he posts on here anyways. Unless they've changed something recently even the games installers transfer via SSL.
Let's let him answer since you don't know his actual situation hey? :-)