Continuity mistake: When Kevin says, "I made my family disappear" and runs around the house, he runs to the foyer and spins in a circle. The window near the stairs is dark meaning it's dark outside. He run upstairs and the window in Kevin's parent's room is also dark. The lights are on too. He then goes to Buzz's room and the kitchen and it's light outside. No lights are on.
Factual error: When Kevin's mom stays behind at the Paris Airport to wait for a flight home, she is shown in a gate area in front of a huge picture window. Outside can be seen an aircraft, a 727 in Eastern Airlines livery, in what is actually Chicago's O'Hare Airport. Eastern never flew to Paris and the aircraft would not have the range for such a flight. Also, you can see a sign that lists Terminal E and F, which are at ORD. They do not have these at Paris ORY.Jorge Suarez
Continuity mistake: Kevin sits down with a meal before the Wet Bandits arrive at the house consisting of macaroni and cheese on a plate. When Harry eventually makes it to the dining room, he is pelted with feathers. Look at the table to the left. A three part microwave meal still in its white plastic container now sits on the plate.
Continuity mistake: Right after Marv loses his shoes on the tar covered stairs he goes back outside to go in the window. When he's running in the snow you can see that he is wearing little pink booties so his feet don't get cold. When he is getting into the police car at the end, you see a short shot of his feet when he's almost in and you can clearly see he has black boots back on.
Other mistake: Toward the end of the film, there is a scene where Macaulay Culkin rides a rig on a rope from his house to the treehouse. Joe Pesci and Daniel Stern try to follow, but Culkin cuts the rope with a hedge cutter. Problem is: The rope is slack when Mac cuts it. With the weight of two grown men, it would have been stressed like a guitar string.
Continuity mistake: When Kevin plays the video when the guy comes to deliver the pizza, the guy on the video says "Hey. I'm gonna give you to the count of ten." When Kevin first saw the movie, the word "Hey" was never spoken. The line immediately before "I'm gonna give you to the count of ten" was "I'll tell you what I'm gonna give you, Snakes".
Audio problem: When Kevin is going through Buzz's private things he finds a picture of his girlfriend. Sickened by her appearance, he smashes the picture. But the smashing sound starts before he hits it. (00:22:05)
Continuity mistake: In the scene where Kevin goes flying into his treehouse and breaks out the wood, the amount of wood missing changes from one scene to the next.
Continuity mistake: In the scene where Harry tells Marv to go down to the basement door, Marv slips on the icy stairs and falls down to the bottom of the stairwell. At the bottom of the stairs from the camera shot from above you can see an accumulation of snow on the stairs and in the bottom stair well. Yet when Marv finally opens the door and enters the basement all the snow that had accumulated in the stair well has now disappeared.