The photo ID file shows that The Joker stands 6'6". In real life and on the show, Cesar Romero only stood 6'3".
When The Mad Hatter grabs Batman and starts choking him, Batman is on the conveyer belt before the sword blades. In the next two shots, he is after the sword blades.
During the recap scene at the beginning of this episode, a sketch of The Riddler's waterworks hideout is supposed to shown, but instead a sketch of Dawn Robbins' penthouse apartment is shown which appeared in "The Penguin's a Jinx" from Season 1.
At the end of the episode the narrator says "next week the Joker returns". Next Week the Mad Hatter comes. The Joker returns the following week.
Trivia: There's no Batfight in this episode.
As Robin jumps from the balcony, it is obvious that it isn't Burt Ward.
When the Bat signal is projected into the sky, the bat emblem on the actual signal and the emblem in the air are two different designs.
For once, The Dynamic Duo enter through the rear of Police HQ.
When Batman tells Commissioner Gordon to be on the lookout for a female suspect, Gordon seems shocked at the thought of a criminal being a female although Robin had mentioned Catwoman only seconds earlier.
When Batman uses Freeze's control box to put his three henchmen in a cold "blue" zone, Freeze runs over to them and yells "Wait, wait!" Batman creates a red zone around the henchmen to drive Freeze back. But in the next shot the henchman are in a blue zone again.
Mister Freeze offers Batman a liqueur and pours it from a bottle. The temperature is described as -50 Fahrenheit. Liqueurs are typically 30-40 proof and freeze at -10 to -20 Fahrenheit.
At the baseball stadium, Sandra says, "Let's just be thankful that my servant and those two simply magnificent creatures, Batman and Robin, are still alive." Her servant was frozen the same as Batman and Robin, but they never suggest that he underwent the same thawing process that was necessary to save Batman and Robin that we see in this episode. It's never explained how he survived.
During the intro that described events of the previous episode, the Batmobile was shown driving in the daytime and outside of Gotham. The events however were inside Gotham and at night.
This episode features one of the scant few times that Robin actually disobeys an order from Batman.
Despite the fact that no one but Mr. Freeze can survive in the extreme cold of his hideout, his butler seems to have managed it when he handed Freeze his sherry, as his hand can clearly been seen placing the glass down outside of the warm red area.
This is another Batman episode in which a character loses their life. The first was in "Smack in the Middle".
When Bruce and Dick head to the Bat poles, a clip from the pilot episode is used to show the book case revealing the secret Bat poles. This is evident as the bookcase prop was different in the pilot episode to the rest of the series (including this episode).
This is one of the very few times when a villain, having Batman and Robin (or at least one of them) in their clutches, actually thought to remove the masks and expose them.
As Chief of Police, O'Hara should know better than to give away evidence as souvenirs, even if he didn't like the look of it.