Continuity mistake: In the department store as Clark is talking with Mary, the lingerie sales lady, his left arm is supporting him on the glass counter as he is standing. The next shot when Rusty approaches, Clark is now bent down with his left arm resting on the counter.
Continuity mistake: After the SWAT team busts into the Griswold's home and an officer yells "Freeze!", Clark's right arm changes position from either being raised or lowered as the scene quick cuts.
Character mistake: When the National Anthem is sung at the end the uniformed police officers should be at attention and saluting. The Lieutenant holding his hat over his heart is totally incorrect. Police and military in uniform keep their hats on, stand at attention and salute. It is correct for Eddie, as a veteran, to render a salute. It's kind of hard to hear, but it sounds like the 2 dads were arguing at breakfast about eating K rations, so one or both probably served in WW2. As vets, they should have also saluted, although it is not mandatory. For the uniformed on duty police it is. (01:32:53)
Continuity mistake: As Clark is stapling the Christmas lights to the house, there are bits of snow and ice on his left-hand glove in the close-ups. But in the longer shots of Clark, the glove has no snow and ice present.
Other mistake: Up in the attic when Clark finds the videos, the video he watches is labelled Christmas '59 but while watching it, the sign being held up says "XMAS 1955"
Suggested correction: It may be a 2nd film he watched after the 1959 film. This may not be in real time, just like we only see Clark in the attic for a few min but in reality the family was gone assumingly much longer than we saw on film and Clark was there longer than we see.
Continuity mistake: After Clark dedicates the Griswold Family Christmas tree and it expands, Ellen's hands are on her hips, but the next quick shot of her shows her hands clasped behind her back.
Continuity mistake: After Clark cuts the rope restraining the tree branches, Rusty is very close to the tree, but the final shot when Clark gives the "OK" sign shows Rusty about two feet from the branches.
Continuity mistake: When they first step up to the tree in the forest, Audrey is still moving. In the overhead shot, she stops, and we can see tracks in the snow where all four have been standing. The problem is, there are a lot of tracks. We're lead to believe they just walked up to the tree.
Revealing mistake: When Snots the dog chases the squirrel into the Griswolds' dining room, he barely brushes a high-back dining chair that immediately falls on its side. If you look closely, a string attached to the the right side top of the chair can be seen tightening which then pulls the chair down.
Continuity mistake: In the scene of Clark standing in the snow trying to figure out why his Christmas lights did not work, the paper he is holding in his right hand is mid torso to him, but in the next shot when Rusty leaves him, his right hand has instantly dropped to his side and he raises his paper-holding hand again.
Continuity mistake: When Clark, Eddie, and Catherine are admiring the Christmas lights of the Griswold house, Clark is very close to Eddie with his left arm draped over Eddie's shoulder, but the next quick cut to Clark when he says, "Eddie?", shows Clark further away and his left arm at his side, and not stretched out.
Revealing mistake: The stunt double for Nicholas Guest is obvious after Julia-Louis Dreyfus punches him. The hair style of the stunt double is different from Nicholas Guest's hair, which is heavily slicked back.
Continuity mistake: In the Christmas dinner scene, closeups of Rocky show his right hand raised to his face, but the overhead shots do not.
Continuity mistake: When Clark is stapling the lights to the roof, his leg is tangled in the sting of lights causing him to lose his balance and slide of the roof. As he slides/falls grabbing the gutter the string of lights around his leg disappears.
Factual error: The family is reacting to where Clark went flying down on his saucer, ending up in a Wal-Mart. With the speed and length of the trip, he would've been out of sight in seconds. There was no way that they could see him from where they were.
Continuity mistake: When Rocky runs out of the RV and stands in front of his mom, her mittened right hand is on his shoulder but in the next shot it's not.
Continuity mistake: After Eddie's arrival Clark is on the lawn with "Snots." Clark's left had is shown as he is there alone with the dog trying to get his attention and his glove and wedding ring have both disappeared.
Visible crew/equipment: Just as Clark is about to smash through the hut on the greased up sled, the shadow of the camera is on the hut. (00:50:57)
Continuity mistake: When the grandfather is sleeping in the top of the bunk bed, there's a cheesecake poster on the ceiling. When Clark falls through the attic floor onto the bunk bed, it's not there.
Continuity mistake: The first time Clark fails with the lights, Ellen's mother says she hopes the kids see what a waste of resources it is. During this scene the level of her martini changes.
Suggested correction: You actually see Clark go from sitting on the counter to bending down as the saleslady is modelling the undergarment.
That's not the part the mistake is talking about. The mistake is valid. Clark is sitting in the counter but is off screen when he changes position (so you don't actually see it). When Rusty enters the shot, Clark's hand is in the counter. In the next shot, his elbow is on the counter, with no time elapsing.
Bishop73