When picking out candidates for the jury, the inquisitor says "You can either stop this shit, or I walk." The guy looks at him and says "Walk." In the next shot, you see his lips move to say "Walk" again, although no sound is heard.
When Milton and Kevin meet for the first time, Kevin says he worked in the Jacksonville DA (district attorney) office for 5 years. Florida doesn't have district attorneys. It would have been the Jacksonville State Attorney's Office.
When John Milton bluffs Kevin and tells him to quit the Alex Cullen case, Kevin's answer is "You know what scares me, I quit the case, she gets better...then I hate her for it". At the end of the movie, when John Milton replays the conversation, he says "You know what scares me JOHN, I quit the case, she gets better...then I hate her for it".
When Kevin embraces his wife in the churchyard, he swings her around and when kissing her ear, takes her pearl earring into his mouth and then gives it back to her. In the next shot her earring is still clearly visible in place although she has not had time to replace it.
When Mary Ann and Kevin are arguing in the living room after she runs from the department store, she is wearing lipstick. As they begin to fight, the lipstick disappears. When they begin to kiss, she is wearing lipstick again. As they make love, it disappears. Finally, as Mary Ann tells Kevin to stop, she is wearing a bright coat of lipstick again.
When Kevin tries to calm a weeping Mary Ann after she has the nightmare, bright sunlight is streaming through the window. A few moments later, it is cloudy.
In the next scene Kevin leaves to find Cullen, and it is snowing.
When Pam talks to Kevin outside the hospital, the shadows show that the sun is not aligned to the street. But as Kevin looks down the street, the shadows are parallel to it. When he looks back at Pam (who has disappeared) the shadows are angled again. And when he starts walking down the street, the sun is once again aligned to it.
When Barbara's father tries to attack Kevin in the courtroom at the beginning of the film, in the first shot he is stopped only by two security guards, but in the next shot - wider angle - Barbara's attorney can be seen standing and stopping him too, to again be calmly sitting in the next shot.
When Kevin first comes back to their hotel room, Mary Ann is on the couch. She begins to speak to Kevin, and she clearly has nothing in her mouth. The next moment she speaks to him again, and she is chewing gum. She then speaks clearly again. In the next scene, she is seen taking gum out of her mouth.
In the courtroom at the end of the film, Kevin returns from the bathroom and sees Mary Ann. She is wearing a bright coat of glossy red/purple lipstick. As he goes to kiss her, she is wearing matte rose lipstick.
In the nightmare scene, we see Mary's eyes open, she gets up from the couch, then we see her back on the couch and open her eyes again (identical footage). But since this is a nightmare, strange things are possible.
By the position of the Empire State Building (which is on Milton's left in one wide angle) visible in the far background behind Milton in his close-ups while Milton and Lomax are talking on the rooftop, it's obvious that Milton is not actually standing on the edge during those close-ups.