Continuity mistake: As Buddy walks out into the street at the start of the movie when the cat is playing dead, you can see several parked cars on the street behind him. When the van backs up to 'catnap' buddy, there are no parked cars. Then as the van drives off again, there is a different bunch of parked cars in the street. (00:03:54)
Audio problem: In the scene after Reese Witherspoon and Luke Wilson are returning from questioning the ex-wife of the murder victim at a spa, they are driving up in Luke's car. You can clearly see, as they get closer to the camera, that what you hear Luke saying isn't what his lips are saying. It was a very obvious dub over...and a very bad one.
Revealing mistake: When Cindy and Buddy get trapped inside the cold chamber, she starts rubbing him to a point that it becomes masturbation. But when she's sitting on his legs doing the thing, in one side shot you can clearly see she is not holding his privates and her hand is just going up and down, closed but empty. (00:58:05)
Plot hole: Spoiler: At the end of the film we learn that the girl is the wild animal, having been saved by the same doctor. Yet at the restaurant she is wearing a bare back dress and does not have the giant X-like scar on her back, like he has or the model has, who the doctor marries at the end.
Continuity mistake: When the two brothers are frantically trying to get out of the car because the monster truck is barreling toward them (in slo-mo), you will notice that the tongue ring is missing from the one brother's tongue. Odd mistake seeing as his character is centered around the tongue ring. (01:27:05)
Continuity mistake: During the detention scene, the teacher comes in and you can see there isn't anything on his rear end. As he leaves, you can see toilet paper hanging from his rear. This was because a scene never made it into the movie where the teacher's office is in the mens restroom. Also confirmed on cast commentary.
Continuity mistake: When Bridget is getting dressed for her big date with Daniel, her tights are over her undies; later, when he's going up her skirt, the tights are clearly under her big ugly undies. (00:17:50 - 00:26:00)
Continuity mistake: When Jo's mother and father are in the garden at Jack's house, she gets in her car with curly hair. The next scene shows her driving her car with straight hair.
Continuity mistake: When Felix looks out at the Anfield pitch you can see executive boxes on the opposite stand. He is meant to be in an executive box but can't be, as only one stand at Anfield has boxes. (01:16:20)
Continuity mistake: Watch the first kiss scene between Reeves and Theron. Keanu's shirt drops to the floor, yet you can clearly see it on his shoulder in every other shot. The camera switches angles multiple times, so this is easy to spot.
Continuity mistake: At the big dinner, the Grandma tries to show the Japanese man some pictures and he shakes his head as he eats his green soup. A minute later, they serve the green soup.