Continuity mistake: When Josh Hartnett is in the hotel dreaming about meeting Lisa, and he is driving around in his friend's Mustang, the wheels/hubcaps on the car keep changing.
Continuity mistake: When the Professor is locked in the rec room, the door opens and while he's shooting there is a round handle to open and lock the door, mounted on the door. When he stops firing the gun, the shot cuts to him then back to the door and the round handle is gone. Later, when someone leaves the room it is back again.
Continuity mistake: As the girls run from the killer, the one girl is shirtless as she starts to run, holding her shirt in front of herself to cover her chest. The camera changes to a rear view and now she is running with the shirt in her hand swinging wildly. The camera changes again and suddenly she is running and putting her shirt on, already pulled over her head, a major change from the last shot. Finally, the camera angle changes again and she has her shirt on completely. All of her shirt/hand positions change instantly between shots.
Visible crew/equipment: When Sylvia and Barrie go inside the house after the children's fight, the camera crew is reflected on the window.
Factual error: The stadium in the opening scene was not around in 1995. The first game played in that stadium was 2001.
Continuity mistake: In Desmond's car, Roy puts on his left sock first, then crosses his right foot over his lap. The shot switches behind him and he is putting his left knee up into the frame. The angle changes again and he puts the sock on his crossed right foot. (00:34:15)
Continuity mistake: When Ben Stiller picks up the Vapoorise to throw it in the bin, he picks it up with his right hand, but he throws it with his left.
Continuity mistake: During the basketball match, when the big guy is making a lot of noise, guards come up to him from the front and behind to take him out of the arena. The guy at the back puts his right arm over the big guy to his chest, but in the front view, that guard doesn't have his arm across his front anymore. (00:03:15)
Revealing mistake: When Gene's bodyguard (the one with the moustache) shoots Slasher and Duke, just before Slasher is shot the bullet hole effect is visible on her forehead (sightly concealed by make-up) just before the actual 'shot'.
Continuity mistake: Bill and Albert are having a drink and smoke by the window when it is raining. The first shot shows the rain thrashing down on the window and dripping off it. But it cuts to a different shot. It is still raining, but there isn't a drip coming off the window.
Continuity mistake: When Jule has found her phone she calls for Jan but then Hardenberg arrives home and catches her. He then wrestles her to the floor, so Jan comes and beats him off her. However, as he wrestles with Jule, her black woollen hat falls off onto the floor. But after Jan beats him off her it is back on her head firmly. (01:02:00)
Continuity mistake: Near the end, Mike is hanging the glass angel he got from Artie on the tree. Nina comes in through the front door, leaving the door chain hanging (unlatched), yet, in the very next shot the chain is on.
Continuity mistake: When Tyler injects Brigitte for the first time at the hospital, look carefully at the syringe. You'll see that in the first shot its content is 1/3, and in the following shot is now 1/2 full.
Continuity mistake: When the girls are looking for food in the container, the blouse straps from the girl on the left change position frequently.
Other mistake: When James Gandolfini hits Ben Affleck over the head with the shovel for burning something in his front yard, he falls, but his head never hits the ground. You can actually see Ben Affleck holding his head up a few inches off the ground. An impossible feat for someone who is supposed to be unconscious.
Visible crew/equipment: When the helicopter lands and the lady gets out, watch as the two men walk in front of it and begin chatting away. In the front of the helicopter, you can see the reflection of the boom mic operator walking around slowly for QUITE A WHILE as they walk by the front of it.
Other mistake: When Jack is reading the paper about the death of two other characters in a hotel, there's a newspaper insert and we can see that, with the exception of the headlines, everything is mumble-jumble, incoherent text just to fill the space.
Visible crew/equipment: While Dr. Kinsey and the president of the university are talking with Dr. Greg about getting a grant from the Rockefeller Centre, in the mirror behind them on the right hand side you can see a crewmember ducking out of sight.
Visible crew/equipment: Within the first few shots when Laramie is driving his convertible down the highway, as the camera first pans across the shiny side of the car, the camera equipment is visible in the glare.
Continuity mistake: Near the end of the movie, Kate's hair is wet and she has a bloody nose. When she finds the platform again her hair is a lot dryer is and her nose is not bleeding.