Continuity mistake: In the opening scene, Mort closes the door of his jeep before he goes into the hotel room. You can hear the sound of the door closing and it's visible in the rearview-mirror. As the camera moves out of the room, the jeep door is completely open. (00:02:05)
Suggested correction: The door just didn't actually catch. I've had cars like that, especially during the winter.
Given that we see it stay closed for almost 4 seconds and hear it catch, it's a valid mistake.
If you've ever lived where it snows a lot, you'd know that door catches accumulate moisture (ice) and can open slowly, as it did in this case.
Continuity mistake: When Mort is trying to figure out what to write, he is pacing around and his hair is messed up. He walks to the chair (hair still a mess) sits down, then in the next shot there is a close up of his face and his hair is perfectly brushed.
Continuity mistake: When Mort is in Ken's office telling him about John harassing him. Ken punches the right side of the chess clock down to start it. Then Mort punches the left side, his right to stop it. Then when the camera switches back to Mort's point of view the the left side is up and the right side is down, then Ken punches down the left side to start it, when the right side should have been the one he had to press down to start it.
Revealing mistake: When Shooter pins Mort against the tree with the shovel, you can see that it's a rubber shovel because it's bending around Mort's neck. [Mentioned on commentary]. (00:40:45)
Continuity mistake: When Mort walked towards Amy after killing her new boyfriend, there is a clear shot of the shovel with no blood on it despite the fact he just chopped a guy through the face.
Continuity mistake: In one of the scenes where Mort is sitting on the couch with the table in front of it, there is a Mountain Dew can on the table and it keeps changing positions throughout the shots to and from Mort.
Other mistake: When Johnny Depp finds the two bodies dead in the jeep, he turns around and spots a squirrel in the tree. We get a point of view shot looking at the squirrel, before Depp faints and the camera starts falling to the left. In the next shot, however, we are facing Johnny Depp and see he has fallen on his right side.
Continuity mistake: Mort throws Shooter's hat over his telephone. The phone is completely covered and the hat has an indentation on top. In the next shot, the phone rings and part of the phone cord is now seen hanging out from underneath the hat and the top of the hat is now perfectly round.
Continuity mistake: While Mort is talking to Amy on the phone near the beginning of the movie, the watch on the table moves from flat on its face to on its side between shots.
Factual error: When Amy tries to escape from Mort in her car, there is a shot showing her feet trying to hit the right pedals to get the car moving. Her car is a SAAB 9-3, but the shot from the footwell of the car is not a SAAB.
Continuity mistake: When Johnny Depp is searching his house for John Shooter, he opens a closet and walks away from it. During several shots you see Johnny and the closet in the background. The open position of the door keeps changing between shots.
Continuity mistake: When Mort is hiding his smoking from his housekeeper, in the third shot the cigarette is burned noticeably less than the second shot.
Factual error: When Amy tries to escape from Mort in her car ,a SAAB 9-3, she starts the car with the gear in neutral (the car has manual gearbox). The ignition key of a SAAB can only be inserted with the gear in reverse.
Visible crew/equipment: When Mort and Shooter are talking next to the highway on the path, a cameraman is visible further back on the trail behind Shooter.
Continuity mistake: There are three different shots on Shooter's script on the porch weighted with the rock. The rock shifts from toward the front door to away from it on the script in different shots.
Factual error: At the climax, Mort stabs Amy in the lower leg. She stands up and leaves a prominent bloody footprint on a stray piece of paper on the ground. Problem is, there's no way the bottom of her shoe could be covered in blood to leave the footprint. She's been bleeding for less than five seconds, and there's no pool of blood for her shoe to pick up and make the footprint with.
Continuity mistake: In the scene where Mort sits at the kitchen table with his PB&J sandwich, the scene opens with a shot of the dripping kitchen faucet. Mort talks to Chico, lays on the floor and then stumbles to the sofa for a nap. Immediately following the nap, he returns to the kitchen sink and there is now a dishrag across the faucet that wasn't there in the previous shot.
Factual error: At the end when the cornfield is revealed, it is in full shade, surrounded by fully mature trees. For corn to grow well and produce, it has to he planted in open fields with full sun exposure.
Visible crew/equipment: When the UPS van drives away after delivering the package, camera and crew are reflected on the side of the van.
Character mistake: After Mort finds the two bodies in the truck, he makes a great effort to avoid leaving any fingerprints on the door handle and also on the screwdriver he removed from the one body and takes with him. However, when he's pushing the car towards the cliff, he reaches in the window to grab the steering wheel with his bare hand, leaving his prints all over it and uses his other hand to push the truck.