Revealing: When the balloon falls on Annie's head, you can see the tack on her head that is used to pop the balloon. It is not just a hair that is sticking up because it is right over the spot where the balloon hits her head.

Revealing: Annie and Hallie come downstairs at the hotel dressed in the same outfits, as their parents tell them to hurry before their mother misses her flight back to England. Nicholas Parker leans over and looks at one of the girls in the eyes and says "This one's Hallie." and she replies, looking straight ahead at him in the eyes. When the other twin speaks, she's looking straight ahead as well, which would technically mean she is looking at nothing.

Continuity: When Hallie is posing as Annie and is going to her mother's house for the first time, a piece of her hair is obviously sticking out on the side of her ear (It's very noticeable). When she gets to the front, and the camera angle changes, her hair is all perfect without any hair sticking out.

Continuity: In the opening scenes where they show the camera girl about to take a picture of them, you can see that there are candles and a flower arrangement on the table. When they open the book to show us the picture of them the candles are gone and the flower arrangement is different.

Continuity: When Annie and Hallie are just about to play cards, Annie spreads all the cards out on the bed and turns them over and then back again. But in one of the shots you can see that it is Hallie who turned the cards over because her fingernails are painted and Annie's are not.