Factual error: Warren Beatty refers to the "Hoover Dam" being able to generate the power needed for Las Vegas and his Flamingo casino. The problem is that he supposedly made the comment in 1937. At that time, the "Hoover Dam" was still called "Boulder Dam." It wasn't renamed to honour President Herbert Hoover until about ten years later.
Factual error: When one of the men visits a doctor and learns he is terminal, the X-ray in the scene is upside down.
Factual error: Why is there a stellar observatory in the middle of a very large city, most of the stars would be drowned out by the city lights to the point of the observatory being useless. Also, the dome is very high up on top of a "building". Such buildings need to flex a little bit in the wind to keep them from breaking, this would make it impossible for the telescope to focus on anything for a timed exposure of film to make those neat pictures of galaxies and such. (00:35:20)
Factual error: In the shot where the laser sights of the assailants come in through the windows and holes in the wall, their angles are far too different from each other. The shooters are standing at a rather great distance from the structure and at more or less the same height. All the laser sights should have more or less the same direction and certainly not make a sweeping motion inside the room. (00:37:30)
Factual error: The movie leaves the impression that Huntsville, Texas and Austin, Texas are just a short distance apart. In reality, they are at least three hours apart.
Factual error: When Javert arrives in Paris to inform the Prefect that he has found Valjean, the government building displays the French Tricolour. This part of the film is set in 1823, during the Bourbon Restoration, so the flag should be the white, Bourbon flag.
Factual error: Towards the end of the film, where St. John is trying to escape with Kim in his private jet, they are apparently attempting to take off from Santa Monica airport. When the camera shows the aircraft beginning its take off roll, the runway markings show that they are using runway 05L to take off from, however, the two runways available at Santa Monica airport are 03 and 21. (01:33:00)
Factual error: Near the end, when Cooper and Rachel are talking in the street, you can see in the background a multi-story brick and glass office building. It appears again a few shots later.
Factual error: Near the end of the chase, when Buddy is ramming the bad guys' car, the scene is supposed to take place in New Jersey as they just crossed the George Washington Bridge. However we see a road sign for NY 100/133, indicating they are back in New York state on the Taconic State Parkway.
Factual error: Riggs is shown using a laser-sight on his handgun throughout the entire movie. However, almost every single time he turns it on, the entire "beam" of the laser is visible, which doesn't happen in real life unless there is smoke/vapor/debris in the air. Obviously done for the sake of the audience seeing where the laser is pointed, but still a mistake.
Factual error: One of the brain surgeons says about Cain's brain, "it's nice and clean in here, there's no damage", except we see throughout the film Cain using the drug Nuke, even a new variation of it called Blue Velvet. When he injects it he's with his chemist Frank, and mentions two of its ingredients, "benzadrine and scopolamine" - no way his brain would be nice and clean.