Continuity mistake: When the Griswolds are driving to the tree farm, they are being harassed by the rednecks in the truck. Several shots of the front of the truck show only two passengers, but one view of the truck through its rear window shows three passengers. (00:04:17)
Continuity mistake: At the beginning of the movie, the Griswold family makes marks in the snow when they arrive at the tree which Clark wants. A shot later, the marks are bigger even though they haven't moved. (00:08:05)
Revealing mistake: When Clark and Ellen are in the bed and Clark's hands are sticky, you can see that he actually grabs her hair to give the illusion that they are stuck, and he turns one of the pages of the magazine just fine. (00:12:30)
Revealing mistake: When Clark is putting Christmas lights on the top of his house, the ladder falls but stays at the same angle. (00:20:50)
Revealing mistake: When Clark starts to set up his Christmas lights, there is a scene where the ladder collapses. If you look closely you can see the wire coming out from under his jacket to keep him from falling forward. (00:20:55)
Continuity mistake: When Clark is outside hanging the lights, he staples the sleeve of his shirt, under his wrist, to the eaves of the house. In the next shot, as he is pulling, the shirt is stapled over his wrist. (00:21:50)
Suggested correction: The position looks the same if you consider hand movement. Look at the opening of the sleeve and the hand position for comparison. I don't think this is an error.
Continuity mistake: When Clarke is installing the Christmas lights, the rope on the ladder keeps appearing and disappearing. (00:23:00)
Continuity mistake: When Clark is holding the gutter, it bends and ice is thrown from inside of it. The problem is that you can't see any ice during the first shot when it bends, and also that the ice goes in the wrong direction. (00:24:25)
Revealing mistake: When Clark falls from the top of his house, he grabs the gutter. It bends and a icicle is thrown from it to his neighbor's house. You can see the thread which guides it. (00:24:27)
Revealing mistake: When Clark is outside at night rigging up the lights, it seems as though the moon is a little too large in the sky. (00:29:35)
Other mistake: Another note about Clark's falling through the ceiling and onto his son's bed: Take note of the shot of him in the attic after falling through the ceiling. He's standing on the upper bunk of the bed now, but from the shot in the attic, he's only down to his knees or so. Assuming his home's ceiling joists are 8 inches or so, then the mattress of the upper bunk would have to be no more than, say, 10 inches from the ceiling for that much of him to still be in the attic while standing on the bed. I've never seen a bunk bed whose upper bed gave you less than a foot of space between mattress and ceiling! (00:33:05)
Suggested correction: The bunk bed is not normally used by two people - there is a scene in the kitchen where Audrey talks about having to share with her brother. It is possible that this bunk bed used to be in a different location, but has been shifted to this lower ceiling at some point in the past.
Continuity mistake: When Clark is outside, trying to get the lights to work, Ellen comes out the door, pulling a sweater around her shoulders. First it is on one shoulder, then both, then one, and at the end of the scene she has it on properly, with both arms in the sleeves. (00:36:10)
Character mistake: Clark has too many lights on his house causing the city to go dark. There is a scene where the power plant needs to boost their output. There is a close-up of a guy flipping the switch. Look at the way they spelled auxiliary - auxilliary. (00:37:54)
Continuity mistake: In an early shot of the outside of the house, the motorhome that Eddie and family show up in is parked in the driveway. The problem is, they don't appear until later in the film. (00:37:55)
Continuity mistake: When Todd, the snob neighbor, falls down the stairs, his wife Margot is not visible in the bedroom. (00:38:55)
Continuity mistake: When Clark finally opens the christmas lights, he has the wires in his hands. The shot later, when all the family comes, the wires are not there and his arms are wide open. (00:39:55)
Continuity mistake: After Eddie et al arrive at the Griswolds, "Snots" is introduced. When everyone else has gone into the house, Clark is left outside with the dog. A shot shows the dog at Clark's side, and if you look at Clark's sleeve, he's wearing a sweater, but actually has on a windbreaker. At the end of the movie, Clark's wearing the sweater. Apparently the shot was taken of him and the dog, and edited back into the film early on. (00:44:30)
Continuity mistake: When Clark and Eddie are standing next to the Christmas tree drinking eggnog, when Eddie walks over to the decoration and knocks it over, in one shot his glass is less than half full and in the next it is almost completely full and he takes a gulp. (00:45:55)
Continuity mistake: When Eddie and Clark are drinking eggnog, Eddie knocks down the decoration with propellers on it. When Eddie walks to the table with the nuts on it the camera shots cut from Eddie to Clark attempting to fix the decoration. In each shot that we go back to Clark, the number of propellers left on the decoration change even after Clark has given up fixing it. (00:45:55)
Visible crew/equipment: Just before Clark goes down the hill on the saucer sled you see the view down the hill. If you look carefully at the right of the screen you can see two pinkish cables stretch into the distance. These are the pyrotechnics that make the explosions Clark sets off. You can see it clearly on the DVD version, but not too clearly in the VHS one. (00:50:15)
