Revealing mistake: Right in the beginning of the movie, we see young Viktor holding a gun to a young girl, about to shoot her. The gun is a revolver and as it comes into focus, you can see there are no bullets in the gun. This is part of a later scene in the movie where Viktor kills his first two people. As he's shooting, you can again see there are no bullets in the gun. (00:01:20 - 00:23:10)
Factual error: The pirates' map shows a drawing of Tower Bridge, which Pirate Captain sees through the telescope moments later. Construction of Tower Bridge started in 1886, and it was completed in 1894. Queen Victoria was 73 when Tower Bridge was completed, whereas she is in her late twenties or mid thirties here. The sign setting the film in 1837 also makes no sense given this timeline. (00:25:20)
Continuity mistake: In the place that looks like a dry cleaner's, Frank is talking to Milo, and Hakan on the couch. Milo makes a crack about Frank's convertible and Frank just fake laughs, and then looks at Hakan on the couch while laughing. It cuts to a close up, and suddenly Frank is looking at Milo and then looks at Hakan on the couch a second time. (00:16:45)
Other mistake: How could Argie and Barker get round the skateboard track and up the stairs to the platform, especially with Barker, in less than 5 seconds?
Visible crew/equipment: As Jack and George enter the boat site they hide behind a red Jaguar XFR. As the camera moves round the camera man is visible in the chrome-work on the Jaguar. (01:35:20)
Continuity mistake: The driveway is clear of snow the day the Baxters move in. Based on the amount of snow in Mason's yard (across the street) and other outside views, there has not been a snowstorm after the Baxters have settled. In fact, the wet roads and melting snow on lawns indicate an ongoing thaw. Christine (Finn's mother) tells the kids they will be leaving to go shopping for a tree and decorations as soon as Curtis (Finn's father) finishes clearing the driveway. Curtis is then shown struggling to use a snowblower to remove A LOT of snow from the driveway (which had been clear of all snow on move-in day). (00:00:58 - 00:18:51)
Factual error: The beginning scene of the film is supposed to be in 1984. An Alf lunch box can be seen being carried by one of the students and Alf wasn't on the air until 1986.
Continuity mistake: While Timothy is saying goodbye to his girlfriend, the girl's birthmark disappears in the shot.