Metro is actually done very well for a book to game. But for a series I'd like to have a shot is Harry Potter. First no actually Harry, get rid of that story. Simply be set in the universe. Another one I'd like would be Eragon. Like Harry Potter I don't like the books, but if this game was to be in the universe of Eragon, it'd be pretty cool. Set in the time when there were dragon riders, and that game world be pretty solid.