Continuity mistake: At the end of the movie, when Clark is outside of the house with Eddie's dog, all the police cars have disappeared. (01:34:10 - 01:35:00)
Suggested correction: It's the end of the movie with credits rolling, I would think the people behind the movie wanted it that way with Clark looking proudly of his Christmas night. his last line in the movie, he said "I did it" and the lights went off on the "THE END" sign. So, that's what I think about the ending. It's not a mistake. It would be if the sign wasn't shut off and started rolling credits after he said his line and nothing's there.
Factual error: In the scene where Clark is working on the lights the full moon is shown. This is December 14th according to the advent calendar. On December 24th when Santa's sleigh goes sailing over the moon, it is still full.
Revealing mistake: After Clark cuts the rope on the large tree, it spreads out and branches start breaking windows. One of the branches has a pole of some type pushing it through the window.
Continuity mistake: After the tree burns up from Uncle Lewis' stogie, he turns around revealing fire on his back. Right as he is turning, the shot cuts to Clark and back to Lewis. In this new shot, Lewis' hair is different (compare the wigs), indicating the person getting the fire on his back put out is a stunt person.
Continuity mistake: In the opening scene, when the family is on their way to get a Christmas tree, they get into a road rage battle. If you look closely at the shape of the headlights, the car the family is in and the stunt car are noticeably different.
Continuity mistake: When the SWAT team charges into the Griswold's house and orders everyone to freeze, Ellen's head is behind Clark's right arm in the shots from the rear, while the shots from the front show Ellen's head in front of Clark's right arm.
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.
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.
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.
Continuity mistake: After Clark receives what he thinks is his bonus check, he says if there is enough money left over he will fly all of the relatives out to see the new pool. Everyone reacts with excitement, particularly Ellen, who is standing right next to Clark. She lets out a cry of excitement and raises her arms. The next shot is taken from the opposite point of view (from over Clark's shoulder). In this next shot, you can see everyone else still excited with the sudden exception of Ellen. She went from shrieking in excitement to having her mouth closed and her arms back down at her sides.
Continuity mistake: When Clark is going into the attic to hide presents, the ladder that smacks him in the face is a sliding ladder, but later when he is shut in the attic and uses the ladder to attract attention it is a folding ladder.
Revealing mistake: When Clark is on the sled, there's one frontal shot when the snow flies in the air before he touches it.
Continuity mistake: The christmas tree is visible from the dining room, but when Lewis goes beside it to smoke a cigar, you can't see him. When the tree is on fire, you don't see Lewis again and you can only see a branch of the tree.
Continuity mistake: When the squirrel jumps out of the tree and the whole family is hiding around the corner in the front entry, the camera alternates shots frequently from the front of the family to the back of the family. Each time the angle changes, Catherine's stance changes from her arm being around Russ to her arm at her side.
Continuity mistake: Less than a day after the ice breaks the neighbors' window, it has fixed itself in the outside shots as Clark is stuck in the attic.
Revealing mistake: When the neighbors fall onto the floor of their bedroom when Clark's Christmas lights finally go on, you can tell a stunt double is standing in for the female neighbor as she falls down at the foot of the bed.
Revealing mistake: After the squirrel lands on the coffee table, it rises up and twitches its tail in a mechanical motion, showing it is really a puppet.
Continuity mistake: As the shots quickly change from the front of Catherine and Rusty to their backs, Catherine is either holding Rusty tightly to her, loosely, or not at all.
Continuity mistake: When Clark falls off the roof, the staple gun goes down before him. In the next shot, it's not heading down from his point of view.
Revealing mistake: When Lewis's coat catches on fire after the Christmas tree explodes, the square on his coat that holds the "fire" is evident.
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.