It appears that some copies of Arkham City are missing the included “Online Pass” code for the on-disc Catwoman missions, which actually locks you out of four missions for the single player campaign. Some copies flat out don’t have the code inside while some have the paper with no actual code printed on it.
It appears this is happening with some of the pre-order and store exclusive Batman skins as well. Hopefully this will be rectified shortly by Warner Bros and Rocksteady, but if you’re missing your code I would advise talking to the store you bought your copy from.
I’m going to hopefully go pick my copy up today and I know I’ll be checking inside at the register.