Continuity mistake: In the scene where Ben knocks on "Sarah's" back door with the apples, the sides of her hair are up and it is evident that there are no visible bruises on her face. However, the next evening at dinner, "Sarah" has her hair down and after moving her hair, a large, fresh bruise is observed by Ben. If this bruise was present, it would have been seen the night before when "Sarah's" hair was 1/2 up.
Continuity mistake: At the end of the film when Julia discovers the cans are all in order, she runs for the front door and see the stereo set up there. Then the husband comes from behind. In the following scenes where she goes to the door to talk to Ben, the stereo is gone.
Continuity mistake: When Sarah/Laura first sees Ben singing and watering the lawn, the view from the inside of her bedroom shows that the room/wall extends quite a ways to her right. But from Ben's viewpoint outside, Sarah/Laura appears in a corner window, with no possible extension of the room/wall to her right anymore.
Factual error: When Julia Roberts first moves to the small Iowa town, she picks perfect fall apples off her neighbor's tree, which draws his attention. But the next day, that tree, and most of the others in the town, appear in SPRING bloom. Some days later, she attends a July 4 parade. That timing might work with the blossoms, but certainly not with the apples.
Factual error: In the dramatic final confrontation, the husband tries to shoot Julia, only to find that the gun is empty. The problem is that slides on automatic pistols like the one used in this scene lock open when the last round is fired. The slide on this gun is visibly closed, so it should still have a round in the chamber.
Continuity mistake: At the end, when Martin has been shot and appears to be dead, he tries to shoot Laura. He then dies, holding the gun in his hand. It's still in his hand when Laura gets up to attend to Ben, who is unconscious by the front door. The shot changes, and Martin is now lying in a different position, the gun nowhere to be seen.
Continuity mistake: Early in the movie Laura's husband smacks Laura on the left side of her head, sending her hard to the floor on her right side. When he comes back later with gifts to apologize, he takes off her dress to put on a red negligeé which reveals a bruise on her upper left shoulder. This bruise was not there the night before when she wore a black backless dress.
Continuity mistake: When Ben brings her the apples she dropped Laura lays the knife she was using to cut up an apple on the table. It is in a different place when Ben puts the apples on the table.
Factual error: When Laura visits her mother in the nursing home, Laura comes out of the bathroom and says that she has her mother's medicine (pills) for her. Meds would not be kept in the patient's room at the nursing home. They would be distributed by a nurse, such as they are in the scene when the nurse interrupts the husband right as he is about to smother the mother.
Revealing mistake: When Martin is at the rest home, he gets a drink from the water fountain and it sprays him in the face. You can plainly see the spray isn't coming from the fountain itself.
Other mistake: When Laura's husband hits her across the forehead, the cut on the left side of her forehead is visible and bleeding when she is on the floor. However, that night when they go sailing, she has her hair pulled in a braid without any bangs covering her forehead and the cut/bruise is totally gone.
Continuity mistake: On the bus, the woman who gives Laura the apple is eating one herself. In one shot, she has only had about two bites, and there is plenty of peel left. About two or three seconds later they cut back to the woman and most of the apple is gone. It would have been impossible to eat it that fast, and there is no crunching bite sound when they cut away from her, and the bite sounds are extremely pronounced in the rest of the scene.
Revealing mistake: In the scene where Laura deliberately breaks the boardwalk lamps, she picks up rocks from the beach and then throws them at the lamp bulbs. However, the first rock thrown misses the lamp bulb completely and in fact, passes behind the lamp post. Of course, the bulb breaks anyway because the explosive charge used to break the bulb was detonated remotely.
Plot hole: Laura moves to Iowa and rents a nice, large house, conveniently furnished with everything she could possibly need, by using a fake name, having no job, no established financial history, has no current bank account or credit cards, or any references. She merely hands cash to the agent to seal the deal. She later lands a job without proof of identity, citizenship (legally required), and has no references, no credible work history, or a different social security number. Laura is resourceful, but certainly lacked the illegal avenues to obtain a convincing fake identity and other false documentation. If she had been able to do any of that, then it would have to be incorporated into the plot as credible exposition. Movies audiences are sometimes expected to employ a "suspension of disbelief" for the sake of the plot, but this stretches credulity.
Continuity mistake: When Laura (Sara) is first looking for a house, she is looking on a tree lined street supposedly in Cedar Falls. The houses shown have only curbs in front but no driveways. Yet the house she ends up renting has a house next door (the one Ben lives in) and there is definitely a driveway out front. Or at least his Mustang is parked there.