Continuity mistake: When the bus is about to jump the ramp, Arnold is on Gerald's left, and Helga is on his right. As the bus runs over the ramp, Helga is missing from the bus, and Arnold is on Gerald's right. While the bus is in the air, Helga reappears, and she is standing where Arnold originally was. When the bus lands and keeps driving, there is one shot where Arnold is missing from the bus, then he reappears, and he and Helga are back in their original places. (01:04:42 - 01:05:22)
Continuity mistake: When Bridget uses her zip line, Helga's arms are folded, and Gerald is standing next to her. In the next shot, her arms are down, and Gerald is standing next to Arnold. (01:07:19)
Continuity mistake: After Mayor Dixie reclaims the neighborhood as a national historic landmark never to be torn down, Phil and Bob go to pick up Arnold and Helga. In the next shot, the people standing around them change position. (01:07:42)
Continuity mistake: When Big Bob throws a model of Arnold's house in the trash it lying on its back but when it shows it again it is standing up straight.
Continuity mistake: In one scene, Grandpa packs up all of Arnold's stuff, but in the scene when Arnold and Gerald have a sleepover, all of Arnold's stuff is back in his room.
