Continuity mistake: Truly crashes into the pond three times: first when the kids are playing in the road and she takes them home, second on the day of the picnic when she says she has nothing else to do and will go on the picnic too, and third at the end of the film when Potts finds out he is rich. In the second of these three, when Mr. Potts carries Truly from her car in the pond, the end of the ribbons on the back of her dress gets soaked in mud, but when you see her again at the beach there is no sign of the dirt.
Continuity mistake: When Finian and Og are talking in the forest, Og is kneeling on a log. He leans over and falls into the river. You can see him completely submerged. He stands up and continues his conversation with Finian while standing in the river and his hair is now completely dry.
Continuity mistake: The ford transit van used by the demolition men Ron and Mr Perry changes between scenes from a long wheelbase van reg no. KGX107D to a standard van reg no. OYO576F.