Yepp, i guess... I have an account on Facebook, but still, the banner under the game leads to some other website, ntku.net, not Facebook, and you get the code there, and enter it in the text field in the banner under the game, so Facebook seems to be not involved in this at all... But, who knows, maybe that website checks if you are subscribed for Nutaku's offical page on Facebook or not, before giving you a code... Not sure about that.