Continuity mistake: When Captain Clown lifts the drum to toss it into the river, the lid shows no holes; Joker punches a few in it earlier. (00:11:55)
Continuity mistake: Batman got rid of the two goons through non-lethal falls, and he is about to face Scarecrow. Scarecrow has his escape planned; he has his right hand on a lever by the armrest...or in the next shot, on a lever above him. (00:18:05)
Continuity mistake: Both Batman and Scarecrow's henchmen are reading the same newspaper, one with a "University Museum Benefit Tonight" headline. The same headline though has a different layout; the words "museum" and "benefit" have bigger spacing in Bruce's copy. (00:10:15)
Continuity mistake: Doctor Long pushes a button on the elevator's board. The key shines bright in close-up, it's not lit in the wider angle. (00:02:30)
Christmas With the Joker - S1-E38
Continuity mistake: The ribbon on top of the big package left by Joker by the antenna is inconsistent in position between shots. (00:12:00)
Christmas With the Joker - S1-E38
Continuity mistake: The Joker's goons blew up the bridge, and Joker turns to the three hostages. Bullock's candy cane is facing Summer's, but the Joker put it in his mouth facing the other direction. (00:07:50 - 00:09:40)
Christmas With the Joker - S1-E38
Continuity mistake: Joker puts in the mouth of "the Lawful family" members candy canes that they can't spit away. He puts back in Summer Gleeson's mouth the cane with the hook pointing up, but it points down when he's done with Bullock. (00:07:40)
Christmas With the Joker - S1-E38
Continuity mistake: In the scene with the old lady and the lad who brings her the package she dropped, the red stripe on the golden package changed position between shots. (00:03:50)
Christmas With the Joker - S1-E38
Continuity mistake: During the wacky scene of the Joker's escape, the balls on the Christmas tree vanish /change position and size between shots. (00:01:35)
Continuity mistake: In the bat nerds laboratory, Bruce Wayne shows them the tape; his hand suddenly turns between shots. (00:12:55)
Continuity mistake: Batman goes in detective mode in the room, and scans it for clues. The shattered object on the desk changed size and placement of the pieces. (00:07:50)
The Man Who Killed Batman - S1-E49
Continuity mistake: Rupert Thorne's eyebrows are briefly white in one shot when he's talking to Sidney.
Continuity mistake: Scarecrow's pants turn red when he's on the catwalk turning on the pump machine.
Continuity mistake: Clayface has clay in the shape of the right hand on his chest when fighting Batman. A few seconds later it's suddenly in the shape of the left hand.
Continuity mistake: When Scarface's gang goes to steal the platinum from the ship and burn a hole in its hull, there is already a stack of platinum bars in their boat before they enter the ship.
Continuity mistake: For one frame during the final battle with the werewolf, the logo on Batman's chest is black and white instead of black and yellow. (00:17:55)
Continuity mistake: When Jervis Tetch is shown he's around 5'5 maybe with blue eyes and sandy white looking hair. Yet the day after his night out with Alice he's suddenly around Bruce Wayne's size with blond hair and his eyes are no longer blue.
Heart of Ice - S1-E3
Continuity mistake: In the wide shot of Batman hanging upside down in Mr. Freeze's lair, his face is blank and the bat outline from his chest emblem is missing. (00:14:10)
Continuity mistake: When the chandelier falls on top of Rupert Thorne, the tommy gun he was holding falls into the bright half of Two-Face's hideout. Later when Two-Face grabs the gun, it is in the dark half of the hideout. (00:19:15 - 00:20:10)
Continuity mistake: When Harvey Dent is walking away from the crime scene, Commissioner Gordon is on his right when next to the police van. Later when Rupert Thorne is watching the news report, Harvey is shown walking by the police van by himself. (00:05:40 - 00:07:00)
Answer: She escaped off-screen and created a copy of herself to fool everyone.