Plenty of current games do this. Battleblock Theater lets you have a character from each of the developer's past games if you have saves from them, and Mass Effect 3 let you have a multiplayer character if you played battlefield 4 and a single player armor if you played the demo of Knights of Amalur. You don't even need to purchase the game on this one, just hand them 5 bucks, get your code, get your 5 bucks back.