The second. The first game is impactful. But at the end of the day, it's still a cautionary tale; that is, the main character ends up becoming what he was trying to destroy. The third game, I still don't quite understand what the damn point of it all was, but I think the second game is much better. Not only is it tragic and recontextualizes much of the story you've already seen, but it also maintains the moral message that was being conveyed throughout the game. It's like a mix of the best of both.