Usually cross-game promotions are confined to one developer or publisher's catalog and are meant as a way to boost sales for whatever the new game is. A good and recent example is Microsoft offering all the Gears of War games to anyone who buys Gears of War 4. Realistically, those older titles won't sell a lot of copies anymore, but it might be enough incentive to get a substantial number of people to pick up the new title. Microsoft's surely operating at a net positive with that promotion.
However, one indie developer is inverting and subverting this model. Amplify Games is giving away its new game Polygod to anyone who has one of several achievements in The Binding of Isaac, a game that it is in no way affiliated with (although, it does share its roguelike roots).
Studio co-founder Dominic Obojkovits explained it by saying "I really loved The Binding of Isaac and I think Polygod will resonate well with players that also really enjoyed The Binding of Isaac. Because of this, I want to reward the most dedicated players with a copy of Polygod."
As Obojkovits said, only dedicated players will fulfill the criteria to get a free copy of Polygod. Of the achievements Amplify chose, less than five percent of players have unlocked the most common one. Here's the full list of achievements that could net you a free game:
via destructoid http://ift.tt/2dq6LZV