Revealing mistake: When Clayface disguised as Joker is holding Talia hostage in the movie theater, they are both standing on stage in front of the screen with a movie playing. However, they are not casting shadows on the screen. Also, no shadow appears on the screen when Clayface takes on his true form.
Plot hole: The side mission "Fragile Alliance" has Batman helping Bane destroying containers full of Titan. After destroying the containers and returning to Bane, a small fight ensues followed by a cut scene of Batman trapping Bane. Bane has the drug Venom visibly going through his body the whole time so he could easily break out, but remains trapped through the rest of the game.