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)
Continuity mistake: When Norman is getting ready to test himself, he lies down on the bed, fastens himself in and the doctor goes to the computer. However, when it shows him being brought in to the chamber he has several electrodes connected to his chest and head. (00:15:20)
Audio problem: After the aeroplane crashed, a dinosaur stepped over it and the windows shattered making the typical sound of made-of-glass things when broken. They are made of plexiglass (a sort of fibrous plastic).
Factual error: When Ray leaves his wife Gina and his car is hit by the truck he should still be in England, but when he is being chased through the streets he is in South Africa, the cops in the car are not in English police uniforms or vehicle, police livery is incorrect, and all vehicles have South Africa plates, not English number plates.
Other mistake: Throughout the film Mason goes through all sorts of shenanigans - explosions, fire fights, falling off a cliff, almost drowning, this woman really goes through the wringer. It's a bit surprising then, that at the very end of the film when the good guys finally come to the rescue that she looks like she has just finished posing for a shampoo commercial with not a hair out of place.
Factual error: The vents that Hunt and his sidekick crawl down at CIA Headquarters are standard galvanized iron box vents; they are very common in the building trade. Try walking or crawling down one - you'll make a noise like the sky is falling down. People will be able to hear you for miles. Every person in that building would know somebody crawling about in the vent system. (This error applies to dozens of films, not only this one).
Visible crew/equipment: When Melissa dodges the truck that has fallen from sky and Dusty rushes to open a door and help Melissa get out of the truck, the reflection of a camera is seen in the bottom right corner of the truck window. As they move out and pan to the right, you can see a reflection of the same camera and cameraman at the bottom right corner of the truck door as they move away. (00:33:50)
Continuity mistake: Gimli is lying with his face under the water, after jumping off the Deeping Wall and landing on the Uruk-hai. In the close-up, the right arm that grabs Gimli's shoulder to help him out of the water is Legolas' right arm. Yet, in the wide shot, suddenly it is Aragorn helping Gimli to his feet, not Legolas. (01:11:10)
Factual error: While Bridger is watching the film of the Mafia boss following Beckerman he signals for the film to be stopped so he can look at the close up shot of the man. He is watching a 16mm film shown through a bog standard projector - stop a film like that for more than two seconds without closing down the projector shutter (this doesn't happen - if it did the screen would darken instantly) and it will melt and catch fire. This doesn't happen.
Continuity mistake: The tyres on the crotch rocket motorcycles they were riding kept changing from knobbly tyres to road slicks, back and forth depending on what terrain they were on. Easiest to see when Ethan skids on the road to avoid the white van - clear shot of slick tyres - then about 30 seconds later they're on the dirt, he skids into the old car and you can easily see that he's got off-road tyres front and back.
Revealing mistake: In one shot when the boat is pulling away from the waterfall, you can clearly see that the shot is the same one they used earlier in the movie. The water from the waterfall now is going up the cliff! They have just put it in reverse.
Other mistake: When Adam comes in and says "when I woke up this morning, the pain was gone", Connie is mouthing his lines behind him.
Visible crew/equipment: The scene where Spencer throws the boomerang for the first time and misses the bikers they take off running. While they are running from the bikers, there is a shot right before the boomerang hits the bikers where you can see a camera man sitting in the bushes on the left side. You don't have to pause it, but can to see it better. (00:36:30)