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
Revealing mistake: Batman and Robin, thanks to the Joker's generous hint, are at the toy factory. In the wide shot just before the phrase "Look sharp, Robin", look at the shadow on the ground; Batman's cape deflates, but the shadow does not move and is still just as wide as it was before. (00:17:10)
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
Other mistake: The train falls off the cliff, explodes, but during the explosion we see bounce off the flames...the train, perfectly intact, even with the lights on. (00:11:20)
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
Other mistake: Joker hosts the show in front of an audience of plywood mock-up figurines. In the wider views we see next to Gordon... Alfred. That would require Joker to know Batman's secret identity. (00:06:45)
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)
Other mistake: When Batman listens to the tape left behind by the security guard (and the police's incredibly sloppy investigation) he presses play and not only the tape is at the right point without him having to rewind, but the recording is much different from the actual events and gives him a convenient abridged version. (00:08:00)
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)
Character mistake: When Batman looks up at the computer the data of the burglaries, he says they happened "this week", but the dates are June 28, July 3, and July 13. On the screen there's also a typo; "Buaglary." (00:05:00)
Other mistake: Batman is reading the front page of the newspaper, but in the drawings that follow, the paper is right-most, it opens to the left of the page. Gotham is not in Japan. (00:04:50)
Other mistake: On the police blimp, the scanner/radar screen in close-up has a single white circle, but in the wider angle it's two black circles, which are even hand-drawn and thus not perfect circles. (00:01:30)
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.
Other mistake: Two Face's lips on the left side are a shade of pink instead of dark red and his coin's all rough looking on the edge.
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.
Answer: She escaped off-screen and created a copy of herself to fool everyone.