Continuity mistake: Quincy is sleeping on the little girl and keeps changing positions on her lap. (00:02:10)
Continuity mistake: The part in Stuart Pankin's hair keeps changing in the party scene. (00:05:40)
Continuity mistake: Playland, Rye NY in the spring, summer and autumn. Alex and the girl walking to the Dragon Coaster. It's spring with the leaves in bloom. Then in stock footage of a different roller coaster being pulled to the top, it's fall with the leaves a golden yellow. Then in other stock footage, the trees are a lush summery green. (01:36:35)
Continuity mistake: The little girl appears to have been given a haircut after we see her at the empty rabbit cage, most apparent when we see her the following morning. (01:27:00 - 01:30:30)
Visible crew/equipment: When Michael Douglas leaves the car rental there is a guy across the street behind a bus conspicuously watching everything. (01:15:45)
Continuity mistake: Early in the movie, there is a black clock on the wall in Dan's kitchen that reads 7:50. Later, when he is in Alex's apartment strangling her, the same black clock is now in her apartment and it, too, reads 7:50.
Continuity mistake: When Michael Douglas comes home the first night after being a bad boy with Glenn Close, he is shown in the kitchen talking on the phone to his wife at a little after 8:30 AM. Not only does he talk to her, but he also has a whispery chat with his lover, walks all about the kitchen, sits at the table, and the time on the clock doesn't change once. (00:22:20 - 00:23:05)
Continuity mistake: At the end Michael Douglas is standing in front of his home with the door open in the background with the hallway illuminated. The camera angle now switches to inside the house, but he has to enter the house through a closed door.
Continuity mistake: When Dan throws Alex into the bath, she goes in face down, but suddenly she is face up - which would be a difficult manoeuvre in a small bath.
Continuity mistake: When it looks like Alex is dead in Dan's bath, she has a long strand of blood coming out of her mouth, but a second later it's gone, and her eyes, which were white, are no longer white - they are open and look like normal eyes.
Character mistake: When Dan and Beth are talking on the phone, Beth says Ellen, their daughter, is five years old, but later, when Dan and Alex are together, Dan says Ellen is six years old.
Continuity mistake: When Alex, naked in bed, jumps up to stop Dan leaving, she attacks his shirt, and you can hear it ripping, but, later, it's completely fine - no ripped bits anywhere.
Continuity mistake: When Dan leaves the budget office in his rental car, the front license plate is mounted off to one side, unusual for this type of vehicle. When he arrives at the house, it's still the same license plate number, but the plate is now mounted on the centre of the bumper.
Continuity mistake: When Dan's wife is by the dinner table talking about the house, his arm is up, yet a frame later from a different angle is down.
Continuity mistake: Dan throws his umbrella and it bounces on the edge of the wastebasket but lands on the floor. When he walks next to the wastebasket the umbrella is now inside.
Suggested correction: It lands on the ground and stays there.
Continuity mistake: After Alex and Dan go dancing and go back to her apartment, she reaches up to get a door key from the top of an electrical box outside her door. She takes down the key in her right hand and then opens the door with her left hand. The key never goes near the lock or doorknob.
Continuity mistake: In the elevator scene as you look down the shaft from above, the air is crystal clear with no smoke in sight. Then in a few seconds smoke appears near the windows but in the next shot when the elevator stops the smoke is gone. (00:20:10)
Revealing mistake: Inside Alex's apartment when the stunt double breaks the glass, you see by the way it breaks that it is untempered glass. This first mess is cleaned up and then they put down other stuff that looks tempered but isn't real glass at all. (01:42:00)
Continuity mistake: As a little girl is sitting on the couch with the dog, there is a book to the left of her which is gone in the next shot. (00:02:35)
Visible crew/equipment: When the family leaves their apartment building you can see the reflection of a boom mike in the right door. (00:09:40)
