Factual error: In the diner, the kids listen to/dance to Britney Spears' "Toxic," which didn't release as a single until January 2004. This takes place in 2003.
Factual error: After the naval battle, Thraex is waiting for an informant who tips him off about Lucilla and Marcus Acacius's plans. And of course, as a well-educated gentleman of 200 AD, he kills time by reading the newspaper. Wait, what? Needless to say (to anyone but Ridley Scott, probably), ancient Romans wouldn't/couldn't exactly get their news by newspaper, the press having not been invented yet. This one looks so modern in its layout it even has headlines and a proper publication title, "Roma Viridia."
Factual error: The movie, by various accounts, takes place 300 years after the apes took over and humans were rendered "dumb" (both literally and in the (non-PC), mute meaning of the word) or went underground. But yet they're making contact with a communication satellite. Satellites don't function for 300 years; they require occasional course corrections to keep from entering the atmosphere and burning up. Course corrections require propellant. The propellant wouldn't last 300 years. And the electronics.
Factual error: A 747 allegedly Air Force One is shown taking off. But it is painted white, not the shades of blue as the real Air Force One is painted.
Factual error: When Santa delivers Christmas presents, he visits Rio de Janeiro, Paris, Sydney, and Tokyo in that order. Due to time zones, the correct order would be Sydney, Tokyo, Paris, and Rio. (01:53:00)
Factual error: Someone shouts "jobsworth" at a London Underground official. This term is first recorded in 1970. The film is set in 1940.
Factual error: When Raban meets the Baron Harkonnen in Harkonnen's bath, the water reaches nearly the top of the bath. As Harkonnen's large body descends into the liquid, the level of the liquid does not rise, in contradiction to Archimedes' principle. (00:46:37)
Factual error: During the scene inside the submarine, you see a Commander (O5) giving orders to a captain (O6). This would never be a thing on any vessel. You would have a Commander as a Commanding Officer on a submarine, but not having a Captain working for the Commander.
Factual error: When Axel first drives from the airport (while on the phone) towards Beverly Hills, he is coming from the wrong direction. He is shown on the interchange from the 105 Freeway westbound to the northbound 110 Freeway heading towards Downtown LA. If coming from the airport to that same intersection, he would be on the 105 eastbound into the 110 - not westbound.
Factual error: The insignia on Staff Sgt. Branson's uniform is incorrect. The insignia on her camouflage blouse is for a US Army Staff Sgt, not a US Air Force Staff Sgt. (00:03:58)
Factual error: The movie is set in the US, but there are several things which aren't found in the US that give away the fact that it was shot in the UK. In one scene, a Tesco superstore can be seen in the background and the lift bridge seen in the film is Kings Ferry Bridge which connects the Isle of Sheppey to the Kent mainland.