Continuity mistake: During the Howard Marks previsions, Anderton notices that the two images of the kid and the man show the kid on different sides. At first, he rotates his hand counter-clockwise (from his point-of-view) to see the image where the kid is on his right, and clockwise to the one where the kid is on the left. The camera cuts away, then cuts back; now the opposite is true (clockwise = kid is on the right, counter-clockwise = kid on left).
Continuity mistake: In the scene when Anderton escapes out of the Maglev Car, we see him jump into a room full of gymnasts. He is on the floor with his legs up in the air, then we see him lower his legs. Yet, in the next shot his legs are back in the air again and we see his legs go down again. (00:43:10)
Continuity mistake: In the scene where Anderton is in flashback to the day he lost his son at the pool, the same woman (of "ample build") walks past him in a pink-ish bikini at least twice.
Continuity mistake: At the beginning of the movie the date is stated as 2054. However, when Anderton has been identified on the metro and data appears on a clear screen, the date he went missing is listed as December 12, 2055. (00:45:10)
Factual error: When they are given the Federal Agent a tour of Pre Crime in the beginning, they say that the victim ball appears on the left and the perpetrator on the right. Yet later in the movie, when Leo Crowe's murder is revealed, Anderton picks up his own ball (the perpetrator's ball) from the slot on the left. If he had wanted to pick up the correct ball, he would have grabbed the one on the right.
Continuity mistake: During the film we see huge highways far above the ground and skyscrapers so tall they have major roads running down them -- all in Washington, DC. But at the end of the film we see a night-time panorama of Washington, and the only tall structure is the Washington Monument.
Continuity mistake: When John and Agatha are in Leo Crow's room, John finds the single photo of Sean and as he looks at it we see the back of the photo and the outline of the boy's image. John then finds the multiple photo-strip of Sean with Leo and holds it in front of him, but as he says, "I am going to kill this man," John is actually holding the single photo - note the outline of only Sean's image on the back of the photo. Next shot he's holding the multiple photo-strip again. (01:42:45)
Visible crew/equipment: When John Anderton shoots Leo Crow, the camera mounted on a crane can be seen reflected on the building's glass in the outside shot just a second before the man defenestrates himself.
Plot hole: Burgess frames Anderton for Witwer's murder, using Anderton's gun in Anderton's house, but Anderton has an airtight alibi; at the same time as the murder, he was arriving at his ex-wife's home. His ex is even on the phone with Burgess, who asks if that's John arriving with Agatha.
Continuity mistake: The front door of Howard Marks house has no windows on the sides and a rectangular transom window above when seen from outside. When seen from inside, however, there are side windows and the transom window is now an elongated half-circle. Also the house is magically huge inside, and not in a way that suggests a conversion of two houses into a single unit.
Continuity mistake: At the start, when John Anderton is going to arrest the man who can't see well without his glasses, he his trying to figure out which house the killer is in. While looking around, his helmet is fastened tightly around his neck, however, as he is racing off to the house he pulls the helmet off in a way which couldn't have been accomplished with the strap still fastened.
Continuity mistake: When John Anderton is fighting off the agents in the car factory, he does a backflip, and then jumps for the approaching walkway, but if you look closely at the floor, the agents feet are visible, therefore signifying they arrived a little early, and stopped. (00:50:40)
Audio problem: When John Anderton's wife throws John's eyeball (stored in a clear plastic bag) onto Tim Blake Nelson's pipe organ, an ongoing organ note is heard, implying that the weight of the eyeball is depressing a key or two. We then see a shot of the eyeball resting on the organ's keys, none of which are depressed. (02:01:20)