Continuity mistake: When Michelle and Leonard are up on the rooftop for the last time, the left side of her hair keeps swapping from being behind to in front all the time.
Factual error: When Natalie decides to rebuild the carburetor that Keith gave to her, she opens the rebuild kit and starts lying out the parts. The problem is that the kit is for a French Solex type 30 single-barrel carb, and the carburetor in the box is a domestic four-barrel.
Revealing mistake: In the opening scene, when Van Damme kicks an opponent onto the boot of a London Taxi Cab, you can see the dent from previous takes.
Revealing mistake: When Ricky and Brandon are on the ferry, the camera shows Ricky reaching down to grab Brandon's butt and then it cuts to Chance and Eddie. If you look closely, Ricky and Brandon are re-creating the scene they just performed.
Other mistake: By the moment that Lea discovers and reads the letter, this, with such typewriting, cannot be written by a six year old boy.
Continuity mistake: When we first see Agent Holloway viewing the crime scene photos taped to the wall, he is facing camera looking at transparent pictures on a transparent wall (as if we are behind that wall, seeing through it). When the angle changes to see the Agent from behind, the photos are now paper photos on a normal, opaque wall and the pictures are arranged somewhat differently - most notably to Holloway's right near the top where two wider photos are vertically aligned atop and below each other in the second shot when they were misaligned in the first shot by nearly half their width. The transparency versus opaque materials issue is a stylistic choice of the director and not a mistake, but the mismatched alignments is a mistake. (00:11:25)
Audio problem: When Pavlov is speaking with the doctor, we hear him finishing a sentence with "say, a doctor, perhaps" but his motionless mouth and jaw show he isn't speaking at all in the side shot. (00:19:00)
Continuity mistake: When King is fighting with Lazarus in the bar, Lazarus gets blood near his mouth like you get when getting hit in the face. But when they fight near the white door, the blood is gone. (01:13:00 - 01:18:00)
Continuity mistake: During the scene that Bo and Sam kiss, his hair changes between shots. From the back, his hair is completely pulled back. From the front, his bangs are down. (01:27:20)
Continuity mistake: Mike Manador watches his girlfriend Gina drive away in a taxi. Behind him a truck can be seen coming down the street. Mike then steps out into street seconds later, but the truck has vanished. Next shot looks up the street and sure there is the taxi but no other vehicles, and you can see the entire street. (01:41:25)
Continuity mistake: The first night in Genova Mary cries and her father comes to hug her. Her hair keeps swapping back and forth from sweaty and stuck to the forehead to loose.
Character mistake: Throughout the movie, all of the drill sergeants and First Sergeant Morley are wearing their drill sergeant badges too low. The badge is supposed to be centered on the right jacket pocket.
Continuity mistake: The neighbors are dripping wet as they get out of the hot tub, yet they don't drip any water when they get onto the trampoline.
Continuity mistake: Gina's father opens the door, club in his hand, and finds his family inside for the surprise party. In the reverse shot, Gina's position is also mirrored, having the right arm raised instead of her left. (00:08:15)
Deliberate mistake: In the final fight, two master Brazil Jujitsu fighters, one an instructor and the other a champion, execute rear naked chokes without the requisite body locks, using the legs to control the body. In the first case, Mike was able to escape the choke by flipping backwards, which a body lock prevents. In the second case, Mike was able to strangle Silva even though any trained fighter could prevent it by simply twisting their body. (01:30:00)
Factual error: Ben stops at a rest area near Hope, BC. He is headed for Vancouver and Vancouver Island. Leaving the rest area, he turns right, as he should, to head for Vancouver. The highway sign points left for Hope, BC, and right for Vancouver. I've been at this rest area, and the direction he turns toward Vancouver is correct. However, the next shot shows him going through Hell's Gate tunnel, which is north of Hope. He would have had to turn left, go through Hope, and 40 or so miles north to go through the Hell's Gate tunnel. The next scene shows him on the ferry to Vancouver Island, which was in the direction he was headed when he turned right from the rest area. There would be no reason for him to turn around and go through the tunnel, as he was already heading in the right direction.
Revealing mistake: At the beginning of the funeral for the girl who died in the motorcycle accident, the supposed corpse can be seen breathing. (01:14:35)
Continuity mistake: When Abby is finished washing the dishes, she tosses the towel she was using and it lands on top of a red can. An immediate close-up of the towel on top of the can proves this (0:25:29). A second later, the picture zooms out again to show her bending over from exhaustion (0:25:30). The towel is no longer on the can, but behind it against the wall. Abby follows the shop owner into a room adjacent to the kitchen and when they come back, the towel is once again on top of the can (0:25:55), but most of it is inside the can this time. It's obvious that neither her nor the shop owner has touched the towel and no one else is in the shop. (00:25:25)
Continuity mistake: Jim, driving Scott home, is smoking a cigarette that disappears before he slaps Scott the second time. There is no smoke in the vehicle that would suggest Jim temporarily placed the cigarette in the ashtray. (00:15:09)
Factual error: Near the end of the movie, a front view of the overdosing/overdosed twins shows Robert putting the dying twin's head on his lap. A close-up of the dead twin shows blood covering most of the left side of her face and a blue tinge on most of the right side, apparently meant to indicate developing livor mortis (bluish color after death). This twin just died, so it is too early for livor mortis to be visible. Livor mortis is not visible to humans until about two hours after death, but the process does begin sooner (about 20-30 minutes after death). Moreover, the writer failed to show the first stage of death - pallor mortis. The twins were Caucasians with blonde hair, so the dead twin would first turn pale (from blood draining from veins in the skin) about 15 minutes after death. The sudden oozing of blood from the dead twin's forehead was also not an accurate portrayal - she was dead, so her heart no longer pumped blood (so gravity takes over, draining blood). (01:39:58)