Other mistake: At the beginning of the movie, we learn that the precogs "do not see what you intend to do, only what you will do" and that they cannot see suicides. At the end, Burgess intends to kill Anderton but does not go through with it; he commits suicide instead. Given these two facts, the precogs should not have seen Burgess' confrontation with Anderton at the end, and a red ball should not have been created.
Suggested correction: Burgess intention was in fact to kill Anderton, but the knowledge of the precogs predicting his murder attempt, the conflict inside his conscious, and the sound of the arriving helicopters made him change his mind at the last second, just like Anderton did in the apartment. The point is they have a choice, and having knowledge of that, only that, changes the future and makes it different from the visions.
Continuity mistake: When we see the Leo Crow previsions for the first time, we see the numbers "9" and "6" backwards because we are seeing the previsions from behind the screen. But in the cyberparlor we see the previsions from the same side that Anderton and Riley are watching them, and the numbers are still backward.
Continuity mistake: As Witwer tells Laura about John's apartment being full of drugs, she's sitting straight up with her hands at her sides, but in the next shot she has her legs crossed and her arm on the top of the painting. (01:10:20)