Continuity mistake: In the first film, it is mentioned several times that Kevin is 8 years old. However, in this film it is stated that he is 10. When his parents are in the Miami airport security office, they say that he was left alone last Christmas. That would make him 9. Both films take place the same days, from about three days before Christmas until Christmas morning, so even if Kevin is born around Christmas time this is still a mistake.
Other mistake: In the scene where Kevin is making the hotel reservation on the phone, the lady does not even ask the dates of when he will be arriving and leaving the Plaza.
Continuity mistake: When Kevin first enters the hotel, he is told to get to the lobby he should go straight ahead and turn left. The next shot shows him turning right into the lobby.
Continuity mistake: When Kevin is running away from Harry and Marv he buys strings of pearl necklaces, and pulls them apart on an icy corner. When the bandits slip on them, there are more pearls there than Kevin dropped.
Revealing mistake: When Tim Curry runs out of Kevin's hotel room after being scared by the inflatable clown doll he hits his knee on a table. When he hits the table and then hops away you can clearly see that he is wearing a knee-pad.
Audio problem: When Kevin plays the tape of his Uncle Frank singing in the shower, it starts with "We know a guy that can really do the cool jerk" twice. Yet, when he first tapes his Uncle, he doesn't start the recording until after that has been sung. The recording also sounds very clear. When he tapes him the door is closed, but the tape sounds the same throughout. Also, when his Uncle says he's gonna "slap him silly" Kevin shuts the door behind him and you can hear it shut. On the tape there is no sound of the door shutting.
Factual error: No airport in NYC has the view of the New York City skyline that Kevin has when he realizes that his family is in Florida and he's in New York.
Continuity mistake: When Kevin is first watching the movie in the hotel room the room service guy already has two scoops of ice cream in the dish and is putting in a third. Then later in the scene the guy asks, "Two scoops, sir?" and only one scoop is in the dish and is just putting the second scoop in.
Visible crew/equipment: In the scene where Kevin lights the rope on fire, he turns to run away. Watch the window he passes, there is a crew member standing there with his arms folded watching.
Factual error: When Kevin goes in the limo, the front desk manager attempts to process a charge on the credit card, which comes back as "stolen." No credit card terminal flashes "stolen" when a credit card has been compromised or cancelled. The machine would simply decline the transaction, much like if the credit limit had been exceeded, or tell the merchant to phone for authorization.
Continuity mistake: In the scene where Harry and Marv are at the skating rink, the front of Marv's hair is constantly changing from shot to shot. It's either poofy or pulled back due to the earmuffs he's wearing.
Other mistake: When the Wet Bandits are stealing the charity money from Duncan's Toy Chest, Kevin takes their picture twice, but only one of these pictures comes out of the camera.
Continuity mistake: When Mrs. McCallister receives the phone call about the police finding Kevin, as soon as she answers the phone, notice the white shirt behind her on the bed. When she tells the family they found him, the camera goes back to her and the shirt is in a totally different position.
Revealing mistake: In the scene at the end when Marv and Harry are talking to Kevin on the roof, if you watch it when Kevin throws the brick down at them, the one brick hits Marv. They cut film somehow so you wouldn't notice easily, but when it hits Marv you can see the corner buckle in, as it's a sponge made to look like a brick.
Continuity mistake: When the McCallister family arrive at the Florida flight and give in their boarding passes, Sondra standing in front of the gap between the man and lady taking the tickets, and then leaving. In the next shot she is standing in the same place again and leaving a second time.
Continuity mistake: When Kevin throws a rock through the front window of Duncan's Toy Chest, the alarm sounds and Harry and Marv run out of the store. In the next shot, the alarm that could be heard has mysteriously stopped.
Continuity mistake: At the pageant scene, when Kevin turns to attack Buzz, you see him make a fist; but when the camera shot changes to include the full choir and the audience, you see Kevin push Buzz with a open palm.
Continuity mistake: When Kevin bumps into the lady at the airport you see the guy who Kevin thinks is his dad run through the door and out of sight. In the next shot, you see him walking through the door.
Continuity mistake: When the robbers are in Duncan's Toy Chest at midnight, Kevin sets up his board on the bucket outside the window. He then knocks on the window, takes the robber's picture, then runs back away and pulls a rock out of his pocket to throw through it. But he wouldn't have been able to run back that far without jumping over the bucket and board, and he did not jump or avoid any obstacles.
Continuity mistake: Once Kevin and the attendant board the plane to NYC to make sure Kevin's family is on board, there is a shot of Kevin while he says, "There's my dad over there." In the background, a man is sliding his black coat off of his shoulders. Two shots later when the attendant says, "Well, go find an empty seat," in the background you will see the exact same man taking his coat off a second time.
Continuity mistake: In the final scene, Kevin approaches the pigeon woman. She says "Merry Christmas" without any pigeons on her head. The long shot is taken, and she now has at least four pigeons are sitting on her head. A close-up is taken when Kevin approaches and reaches her hand, and again, pigeons have disappeared from her head. Impossible to have the pigeons flying on and off her head in the space of half a second.
Continuity mistake: After Kevin throws a few bricks off the roof, a brick is lying at Marv's feet. In the next shot, it is gone. When Harry disappears, we see three bricks, all on the road and none by Marv.
Continuity mistake: When Kevin is throwing bricks from the top of the apartment building, note the position of the gym bag beside Marv - it is in the wrong place, positioned differently, during one of the cutaway shots between Marv and Kevin.
Other mistake: When Marv ends up stepping on some green gunk that Kevin set as a trap in the basement, he eventually slips and then slides into a shelf of paint. However, Marv actually started sliding after he fell to the ground. It's almost as though he was being pulled forward. How could he have slid?
Other mistake: In the scene where Kevin is being chased through the Plaza lobby, the large brass/marble table, usually in the center of the room, has been moved to one side to allow the characters to freely run through the area. The table has been purposely moved as it is right next to the concierge desk which would pose an inconvenience to any guests and so, therefore, is not a natural occurrence. After all three fall over, it is evident that a large space has been cleared, as it allows for Cedric to be dragged away as well.
Continuity mistake: Kevin is being served ice cream in his hotel room. A wide shot of the bed shows the food around it and the waiter scooping ice cream into a bowl. Look at the tall pink rose at the end of the bed, which towers out of its vase. In a couple of shots later, the rose suddenly becomes barely higher than the vase itself.
Continuity mistake: When Kevin is buying some toys at Mr. Duncan's Toy Store, he pays for the toys and there is a can full of pencils to the right of Kevin. As the camera switches shots to Mr. Duncan and back to Kevin, the pencils are in different positions every time.
Continuity mistake: Kevin takes photos of the Wet Bandits robbing Duncan's Toy Chest. Later on when the police look at a photo, it doesn't match up to when it was taken - they didn't have money in their hands.
Revealing mistake: When Kevin arrives at the airport in New York (filmed at Chicago O'Hare) and goes up to the agent to ask her what city is outside the window, one of the destinations on the board at the gate is New York - LaGuardia...giving away that the scene was not shot at a NYC area airport.
Continuity mistake: Kevin's mom goes to the 3rd floor to lecture Kevin. When Kevin stands they move shots between mom and Kevin who is standing still. There are 3 separate shots of Kevin in this sequence. In the 1st & 3rd shot his left collar button is covered and his hair bang is above left eyebrow. In the second shot the left collar button is visible & the hair bang is lower touching the left eyebrow.
Factual error: The picture that Kevin takes of Marv and Harry through the toystore window is perfectly clear. There is no way you can take a picture of something through a window without the flash reflecting back and ruining the image, especially from as close a range as Kevin was.
Continuity mistake: When the McCallisters are at the police station, the cop puts downs the phone and tells them there is "No sign of him." Behind them, the coffee pot is half full and a lady in a multi-coloured top talks with another cop. In the next shot of the McCallisters, the coffee pot is almost empty, a coffee tin with a red lid appears (that was taken away in an earlier shot) and a completely different lady talks to the cop behind them.
Continuity mistake: When Kevin is checking into the hotel you can see a pair of legs in the top right hand side of the screen. At one point they walk away and then are back in the very next shot to continue standing while Kevin talks to the hotel lady.
Continuity mistake: When Kevin is running from Harry and Marv he breaks a fake pearl necklace to spread the beads all over. You can see after he drops them all that they have spread far apart. In the next shot where Harry and Marv's feet are shown there are a lot more beads all together which is why they slipped on them.
Factual error: When Harry and Marv arrive for the first time at Kevin's "funhouse", they look up to the roof and spot Kevin taking a Polaroid of them. The flash brightly illuminates them both, but the building looks to be at least 30 feet high; a basic Polaroid camera does not have a flash strong enough to reach such a distance (plus the street is already illuminated by lamps and Christmas lights).
Continuity mistake: At the end, Harry walks to the building's door, thinking he can get in. The bag with tools opens and tools fall all over him. After a few scenes, he gets up and you can see that the tools are in one place and not scattered anymore. Plus the bag and string have disappeared.
Continuity mistake: Take a look at the position of the penknife when Kevin is paying for the toys and chatting to Mr Duncan. In one shot it's in line with the camera, on its front. The next shot (10 seconds later) the penknife is on its side and lined up with the book. Mr Duncan did not touch them in this time.
Continuity mistake: When the vans from the airport arrive, notice the second van to arrive smashes the statue in front of the McCallister's door all over the pavement. When the whole family is running out of the house into the vans, the statue is standing perfectly again like it hadn't been touched at all, but pieces of the feet were broken off, so it couldn't have just been stood up again.
Continuity mistake: When Harry goes up the steps leading to the back door of Kevin's uncle's house, the wooden planks he kicks away are in a different position to when he first enters the alley.
Visible crew/equipment: As Tim Curry exits the lift to secretly search Kevin's room, at the bottom right hand corner a shadow that looks like a hand appears on the wall to the left of the lift, inconsistent with the movements of him exiting the lift. You have to be quick, as it appears on widescreen as the shot moves away from the lift doors.
Other mistake: When the McCallister family is in the Chicago airport and Kevin is changing his batteries, on the P.A it says that American Airline flight 226 to New York is in the final boarding process, and Kevin runs after the man who is running to the gate. Once they are on the plane, the flight attendant announces, "Welcome aboard American Airlines flight 176 non stop service to New York." These are different flight numbers.
Revealing mistake: In the whole scene where Harry's head is caught on fire to the part where it shows the explosion outside the building, this is quite obvious that the whole scene was done during the day.
Continuity mistake: Kevin asks the limousine driver, "Do you know any good toy stores?" His glass of Coke is almost empty. When the driver says, "Yes sir.", it is three-quarters full.
Revealing mistake: In the scene where Kevin runs into his relative's abandoned house in the middle of the night to set the traps, he runs down a ramp. You can tell that shot was filmed in broad daylight.