Superheroes and villains in video games are notorious for leaving behind interesting and sometimes hard to find easter eggs. From The Fantastic 4’s building in the PS1 release of Spider-Man, to the hint of a sequel almost never found in Batman: Arkham Asylum, crime fighters often leave shout outs to their friends and creators in their path.

Batman: Arkham City is no different. With subtle hints of future story lines and nostalgia, players find more and more easter eggs around every corner. So far gamers have discovered bits and pieces of Scarecrow’s future plans for Arkham, his secret codes found in radio signals, and even Azrael looking down on a young Bruce Wayne (I assume he must have known Batman’s true name all this time).

Even though so much was almost immediately found by Batman fans, Rocksteady says there are a few left that no one has reported finding. They have not given any clues as to what these easter eggs are, or where they are located. Rocksteady simply stated that not all of them have been found, and that they are probably extremely subtle hints.

So, what are these mysterious hidden easter eggs? Could be anything. Perhaps there’s another preview of the next game hidden somewhere deep in Arkham, or maybe another unseen villain stalking Batman somewhere in the game.