As Mr. Poe is introducing the children to Dr. Montgomery they all enter Dr. Montogomery's House. As Mr. Poe is the last one to enter he reaches to close the door. In the very next scene he again walks through the door and reaches to close the door for a second time.
At about 13:36, after Monty says, "You know, I've always wanted to have a family of my own," the same clip of the children is used immediately after when he continues saying, "but time flies like a winged lizard." Notice Sunny's arm position and Klaus licking his lips.
Sara Canning's character's name is spelled 'Jacqueline' in the credits for the movie that the Baudelaires and Uncle Monty go to see, but is spelled 'Jacquelyn' on the poster seen in the lobby of the cinema. It is spelled 'Jacquelyn' in the end credits.
The long shot of the theater seats from the projection booth shows empty seats where the children are sitting, and fewer people than the shots from the front.
The amount of popcorn in Count Olaf's giant popcorn bag changes dramatically several times after he has it refilled.
When the children pull Count Olaf back to his seat, the little old lady says "Get out of the way", but her lips don't move.