Revealing mistake: When the Penguin is sliding down the zip line, just before he hits Batman you can see Batman throwing a punch at nobody, he is swinging at empty air.
Revealing mistake: In this scene we see Frank Sinatra in a diving suit and helmet being lowered into the sea to look for a sunken submarine. As he is being lowered you can see the sun's reflection on the walls of a tank, meaning it was filmed in a large tank of water.