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.
Continuity mistake: The tiger bites the seat off the suitor's trousers, allowing the viewer to see his polka-heart boxers. When we see the tiger in the courtyard, he has a part of the same boxer shorts in his mouth. So if he bit off the seat of the trousers, shouldn't he have purple cloth in his mouth? (00:11:45)
Continuity mistake: When Adam Banks is playing in one of the games, he scores a goal and his teammates on the bench stand up and cheer when he scores. Problem is, Adam Banks is on the bench too.
Revealing mistake: When the kids are burying Gus, his supposedly dead face flinches when they shovel dirt on him.
Continuity mistake: In his cameo in this film, Tim Burton is holding something in his left hand that looks like a remote of some sort when we first see him in the background. Then the shot changes to Debbie and back to Tim, but this time he doesn't have it. Then the shot changes to Debbie again and then back to Tim, and he reaches to his far right and picks it up.
Revealing mistake: When the terrorists drop the dead body out the aircraft door, look closely at the aeroplane just beneath the door, you can see the reflection of the mat the stuntman lands on, as well as the spotters around it.
Other mistake: During the scene where Markus and Jackie are making love for the first time, as she is straddled on top of him, you can see that she that she is wearing knickers (panties).
Other mistake: In the scene following the robbery, the four young men, led by Tupac Shakur and Omar Epps, run into a brick court, walled on four sides. Shakur states he's going to keep the gun, despite suggestions that they ditch it. He has a revolver stuck in his jeans, by his left hip. When he is challenged about keeping the gun, he pulls another revolver from his pocket, scuffles with one of his friends and shoots him in the chest - all the while the grip of the other identical revolver is in view.
Other mistake: Towards the end where they steal the chip, they are detected and about a million security guards are all running around, yet 30 seconds later, the only security guard is one man with a shotgun. What happened to their big army of security guards? (01:41:30 - 01:42:55)
Continuity mistake: As Jack Kelly rides the horse near the end of the "Santa Fe" sequence, his hat is waving behind him. When it cuts to a different angle the hat is on his head. Note: This was a specific detail put in by the director, symbolizing the boy's mental transition from New York to Santa Fe. However, it failed and is commonly seen as an editing mistake.