Other mistake: After King Tut's men deliver the statue, it's referred to as a Sphinx. Even Batman says, "Rather good imitation of the 4th Dynasty's Sphinx at Giza." Problem is, the Great Sphinx of Giza is a reclining lion with a human head. The statue in Gotham's park is a ram's head atop a seated human body, resembling Egyptian God Khnum, and looks nothing like the Egyptian Sphinx. Bruce Wayne is a member of Gotham City Museum's Board of Trustees, which recently opened the new exhibit of Egyptian antiquities. (00:10:35)
The Penguin Declines (3) - S2-E39
Continuity mistake: When Joker's goons return from Operation Laundry Bag and finally release Penguin from the bag, Penguin's hat is secured on his head with an elastic strap, but this strap vanishes in the next shot. (00:04:30)
Continuity mistake: While Bruce Wayne is lying on a gurney at the back of the ambulance, in the wide shot of Tut's henchmen driving along on the street, there's a rearview mirror on the windshield and a single beacon light on the roof, but in the closeups the rearview mirror is gone and there are two beacon lights on the roof. (00:21:30)
Smack in the Middle (2) - S1-E2
Revealing mistake: While Riddler is with the unconscious guests at the Moldavian exhibit, in the basement of the Moldavian Pavilion the Mole Hill gang blow up the ceiling to create an entry to the exhibit, on the floor above. They lean two tall ladders at the side of the hole and climb up. When Riddler makes for an escape Batman follows him down below, and now we can see long metal brackets bolting the ladders to the floor for safety. (00:20:20 - 00:22:00)
Caught in the Spider's Den (2) - S2-E56
Audio problem: The sound effects are inaudible when Robin is punching Black Widow's henchman when she talks about where her short-circuiting device is.
A Riddling Controversy (2) - S2-E46
Continuity mistake: At the end, Riddler's moll Anna Gram's earrings disappear, just as Batman and Robin arrive before the fight.
The Clock King's Crazy Crimes (1) - S2-E11
Other mistake: When Clock King activates the coils to ensnare Batman and Robin, the coils ensnare Batman first, while Robin just reacts. In the next shot, Robin is tangled as well.
Other mistake: When Tut's henchman slowly reads that Bruce Wayne will donate his talking sphinx to the Black Museum at Scotland Yard from a newspaper, a close-up shows he is reading it upside down.
Death in Slow Motion (1) - S1-E31
Continuity mistake: Van Jones is very upset at Riddler's Charlie Chaplin impression, but in a wide shot, he is smiling with everyone else.
Continuity mistake: At the very end of the episode, when Batman, Robin, and Batgirl find out Joker is released from prison, one shot shows Joker in his usual pink suit. But in the very next shot, his suit is gray.
The Bookworm Turns (1) - S1-E29
Other mistake: When Gordon falls into the water after being shot, the footage is in black and white, vs in color.
The Pharaoh's in a Rut (2) - S1-E28
Continuity mistake: When the fight starts and after Batman gets into the sword fight with Tut's henchman, Tut's women start to leave. But in the close-up when Batman states he stayed sane by reciting the multiplication tables backwards, the women leave again.
Continuity mistake: At the beginning, in the wide shot of Batman and Robin over the candle dipper, Riddler is standing with his back towards them, but in the close-up, he is facing forward.
Continuity mistake: There is a jump cut at the beginning when Batman and Robin are being lowered into the vat of wax, where all of a sudden, Batman is trying to wiggle his legs free.
Louie's Lethal Lilac Time - S3-E18
Character mistake: When Gordon and O'Hara show Barbara the slides of Batman and Robin's previous exploits, the last slide shows the Batmobile being hit with mines. Gordon says they're chasing King Tut, but it's actually from Catwoman's "Better Luck Next Time".
True or False-Face (1) - S1-E17
Other mistake: When False Face lifts the wig off Blaze to reveal the crown that is on top of her head, you can see it is not there until the next shot of her.
Not Yet, He Ain't (2) - S1-E22
Revealing mistake: When being gunned down by O'Hara cops, there are no bullets coming from the cop who gunned Batman down, but he still reacts to it.
Not Yet, He Ain't (2) - S1-E22
Continuity mistake: When Batman and Robin are being chased by O'Hara and the cops, Batman raises his hand, goes to throw a smoke grenade, then in the next shot, he raises his hand again to actually throw it.
The Sandman Cometh (1) - S2-E33
Continuity mistake: As the batfight ends and one of Sandman's henchmen hits Batman with a bolt of cloth, he goes down and is buried with mattresses on the right side. But when they remove the mattresses to wake him up, he is facing forward.
Continuity mistake: Tut's crocodiles are menacing in the close-up, but in the scene where Robin is over the moving ledge, the crocodiles are very fake.
Answer: It's wasn't unusual for multiple actors to play one character on this show. The villains on the TV Batman were played by guest stars, not regular cast members. George Sanders, Otto Preminger, and Eli Wallach played the part at various times. They may simply have only wanted to play the part once or twice, or they were later tied up with other projects, making it necessary to cast someone else. Other characters, like Catwoman, were also played by more than one actress.
raywest ★