The official Twitter for Arkham City @arkhamcitynews has posted a new trailer for the game, featuring another one of Batman’s most classic villains, The Riddler. But, there’s a little more to it than that. Apparently there is a riddle hidden inside the trailer, and if people can solve it, some exclusive Riddler concept art will be revealed on friday. Wanna give it a go? Then hit the jump, check out the trailer and join the discussion here.