Continuity mistake: In the car, before entering her mother's house, Annie is wearing a plastic watch, but when she hugs her mother she is wearing a metal watch.
Suggested correction: Actually, it's Hallie not Annie. And she is obviously wearing a metal watch in the car and when she hugs her mother, not a plastic watch.
Factual error: Hallie, in London, dials the operator and says she wants to place a collect call to Napa, California. The phone rings once and Annie answers, then begins talking. On such a call, the operator should have told the recipient, "You have a collect call. Will you accept the charges?"
Revealing mistake: When Hallie and Annie are fencing with each other, Hallie forces Annie's sword into the air, and Annie runs towards the hay stack in the background to catch it. The sword lands on top of the stack of hay to the left of the screen and bounces out of sight; Annie then catches another sword that falls from above, that someone obviously dropped for her to catch.
Continuity mistake: When Hallie and Annie get out of the water bin after their fence match, they both take off their helmets, revealing Annie's messy hair. In the next few scenes, you see the hair a little less messier than before and neatly pulled back.
Continuity mistake: When Annie and Hallie are dragging Meredith's airbed into the lake, a close-up of the girls at the water's edge shows the one in a blue plaid shirt with her sleeves rolled up. In a long shot behind them, her sleeves aren't rolled up.
Continuity mistake: When Annie is entering her home in London, she puts her hand on the doorknob and pushes the door open. In the next shot when it shows the entryway with the door opening, there is no doorknob.
Visible crew/equipment: When Dad shows Mum his wine collection and the wine from their wedding, you can see a microphone dangling right over Dad's head.
Suggested correction: Sorry. Looked at it closely. Can't see any microphone. His head shot is so close to the top of the screen the entire time, there's no to very little room to show anything above his head.
Continuity mistake: In the opening scenes when you see the limo pulling up to let Annie and Martin out you see the pavement to the right of the limo has a lot of sunlight on it. When they get out and are standing on the pavement, the sunlight is gone.
Continuity mistake: When Hallie and her mom are having tea, you can see a watch on the mom's wrist. After Martin hands Cuppy to Hallie, in the next shot of her mom, there is no watch. (00:40:05)
Continuity mistake: When the twins are standing on the steps of the isolation cabin, talking about their familes, Hallie, one time is not looking at Annie - her eye-line for the special effect is off.
Factual error: At the hotel, Chessy's door to her room stays open after she goes into the other room to discuss the whole 'dad doesn't know' matter. In real hotels, the guest-room doors have auto-closing mechanisms for fire safety and security. The door would have swung closed and locked Chessy out, but even though this is a 4 or 5 star hotel which would be fully equipped as far as modernity's, it doesn't.
Continuity mistake: When Annie and Hallie are playing poker, Annie puts down a pound. In the very next shot, when Hallie puts down a £5 note, the pound is gone. There wasn't a big enough pile of stuff yet to hide it. (00:14:35)
Suggested correction: Hallie doesn't put down a 5 lire note. She puts down an American $10 bill.
Audio problem: When Annie is saying goodbye to her butler Martin and they perform their legendary handshake, Annie is the first to put her hand down when they stack their hands, however you hear a clapping sound.
Continuity mistake: After Annie first meets Meredith (playing Hallie), when she's sitting in the red water floater, her necklace goes from tucked inside her bathing suit to out, then to in again.
Suggested correction: There's no mistake here. Hallie's necklace barely reaches the top seam of her bathing suit. It could easily slip halfway in and halfway out on its own.
Continuity mistake: When Hallie (posing as Annie) arrives in London, she is seen sitting on the left seat in the car when she's on her way home, passing by the various spots in London. However, when she reaches home, she is sitting on the right side of the car. Unless she was sitting alone, this is not logical as Martin was sitting together with her at the back of the car.
Character mistake: Just before Annie and Hallie find out they are sisters in the isolation cabin, Hallie says "Oh hey, it stopped raining!" But you can see outside that it is still raining at a significant rate.
Suggested correction: That's just water dripping off the roof. It was raining before she said that, but obviously quit raining, and then she said, "Oh hey. It stopped raining." It was not raining when she said that.
Continuity mistake: During the scene when Hallie and Annie are seen lying next to each other, Annie's ponytail goes from in front of her to in back in some shots.
Audio problem: In the scene where Hallie (pretending to be Annie) meets her mom for the first time, right after her mom says "No I absolutely love it" going to the next shot, you can see Hallie taking a breath. After she closes her mouth, you hear that breath.
Plot hole: When Annie (pretending to be Hallie) lies to Meredith about her father's "routine" with ladies, she mentions how he gives them a bottle of his "special reserve label wine." He then approaches them and really does offer the special reserve to Meredith. It's impossible that Annie was able to predict this. She expected her father to be single, based on what she was told by the real Hallie. Neither girl could guess how he behaves with girlfriends.
