Factual error: When McClane and Zeus take the little hatchback from the bank location, they run up the ramp by the Brooklyn Bridge and McClane looks to see the dump trucks aren't on the bridge. Zeus then spots them on FDR Drive and they speed off down the ramp to FDR Drive. The ramp they were on doesn't connect to the ramp they took to give chase. It only heads towards City Hall or over the bridge. They'd have to take the Civic Center ramp, do a u-turn under the Brooklyn Bridge approach then head back up the ramp to FDR Drive.
Factual error: Throughout the movie, all sorts of messages are passed over the 1MC (ship's intercom) when the boat is supposed to be stealthy. They've set "Ultra Quiet" to avoid the enemy sub but no-one was any quieter, and everyone was still using the 1MC. Worse, people are shouting commands and status updates, both in person, and over the intercom! No wonder that Akula found them. The only thing protecting this ship was plot armor! In real life, messages would be passed quietly using sound powered phones (which we also see), rather than blasting the info loudly to the entire crew, because sonar will literally pick up the sounds of loudspeakers and people shouting. Let's not even mention classified target data being passed to the entire ship's crew on the 1MC. (00:49:00)
Factual error: Angela Bennett finds the Praetorian's IP while using the PC in the Cathedral's bank: it's 23.75.345.200 - they want us to believe that this is an IP, but no IP can contain numbers greater than 255. [Common practice, like fake phone numbers, but still worth noticing].
Factual error: When the porter first gets ready to shoot at the terrorists (after Ryback falls off the train) he goes through a series of verbal instructions to remind himself what to do. The very first thing he says is "safety off". The problem is that the gun he is using is a Glock pistol. Glocks use a device called a "safe-action trigger" but they don't have a manual safety that you turn on and off.
Factual error: Princess Isabella was a 13-year-old girl living in France when William Wallace was executed in 1305. She didn't marry Prince Edward until 1308, and the marriage took place in Boulogne, not London.
Factual error: Near the end of the movie, as the money train is approaching the passenger train, the motorman is communicating on the microphone with dispatch. If you notice, as he is talking, his hand is NOT on the throttle. On the trains in the NYC subway system if the throttle is not depressed the train will stop.
Factual error: Various Sydney landmarks can be seen throughout the movie (although the Centrepoint Tower and the Monorail play major roles). There are also some cars that have right-hand steering wheels despite the story being set in California, and some Australian model traffic lights (foot-long black cover with a grey pole) can be seen when the Scorpion bot destroys a car in front of the Rangers. (01:06:00)
Factual error: When Gadji hears Ace imitating a gorilla, he says 'Silverback'. In the next scene he says to Mick 'Female'. A silverback is the dominant male in a gorilla group, named for his coloring. See http://www.wwfus.org/gorillas/species.cfm.
Factual error: The Smokers' plane is shown with every surface completely rusted reddish-brown. But planes are made from light alloys, not steel. They can eventually corrode - very slowly - but the film of corrosion is white, not red like iron rust.
Factual error: When Bond fights with Xenia in the sauna, she wraps her legs around his torso. He tries and fails to get them released, but he does create enough space between her legs which would, realistically, release the pressure on his body. (01:03:00)
Factual error: When Van Damme goes on the ice to play Brad Tolliver he punches the player with number 22, which actually was the number of Christian Ruuttu, but the player who got hit is called Dupinsky afterward.
Factual error: As Al Pacino is catching up to Robert De Niro on the freeway he uses his walkie talkie to get an update on De Niro's location. He does not take his finger off of the talk button and therefore would not be able to hear the helicopter pilot's response.
Factual error: When Banderas is in the hotel room with the four dead guys, he realizes that Stallone is in the other room. When Banderas looks at the hotel TV screen, it displays the in-room guest service welcome page: "Welcome to Marriot's In-Room Guest Services". The hotel name is misspelled, while the spelling in the logo above it is correct.
Factual error: Sharp, distinct text and even graphics are shown projected from an early laptop screen onto the faces of Angelina Jolie and Jonny Lee Miller and even against a wall several feet in the background (starting 0:50:35 and throughout the rest of the movie). Of course, computer displays have never projected sharply-focused text or images onto user faces or any other nearby surfaces. (00:50:35)
Factual error: When Gene Hackman is shot at the end he looks down and sees the hole in his shadow. However if he was shot from someone at the same level as him, the hole would be straight, parallel to the Earth's surface. So if he could he the reasonably proportioned shadow the angle of the sun wouldn't show any hole in him at all.
Suggested correction: First, it is reasonable to assume that Hackman is significantly taller than Stone, and, given that she is firing from a hip draw the angle of entry for the fatal gunshot would be on a upward trajectory. This generally upward bullet trace combined with the evening or late day sun could be reasonably expected to cast a shadow if you suspend disbelief initially to allow that this type of wound is practically plausible.
The fact that she is shorter is irrelevant given the distance between them. For the angle of the light showing through him to make sense (and that's assuming it makes sense for it to show through him at all) she would need to be kneeling directly in front of him. The fact that, as you say, suspension of belief is required demonstrates the original mistake is valid.
Suggested correction: He doesn't see the hole in his shadow. We see him look downward slightly, then we see the shadow slightly from the side, not the view he would see. We then see him looking down at himself. It's easy to assume he is looking at his shadow, but we don't see him doing that. He could simply be staring into space, with the shadow presented for dramatic effect for the viewer.
Factual error: James Graham, 4th Marquess of Montrose, became 1st Duke of Montrose in 1707, six years before the film is set, although the film refers to him throughout as a Marquess.
Factual error: When Baldwin is in the old Caddy convertible driving alongside the train, he sets the cruise control so that he can jump into the train. There are three problems with this. I seriously doubt a Caddy that old, it looked like early 70s, would have cruise control, but they were luxury cars, so it is possible. They show a shot of him setting the cruise control, and it is on a modern-style control stalk, very typical to late 80s and early 90s GM cars. Since the ground along a railroad track is not pavement, it would be very bumpy and uneven, and virtually impossible for the cruise control to keep the car going whatever speed he wanted it to go, going over dumps and holes like that.
Factual error: When the hovercraft is stopped after Jackie cuts the side open, it isn't slanted to one side(from the outside view), it is straight.
Suggested correction: It is slightly slanted... it's just hard to see with the camera angles, since it's mostly shot from the side once it crashes.
Factual error: At the end when the oil in the cavern is burning there is no sign of smoke. With a fire as large as it appears to be, everyone in there should be choking to death, yet they don't even seem the least bit bothered. Forest Whitaker should have also been roasting over the flames, yet he is unscathed.
Factual error: In the opening scene with Doug Masters flying in Russian airspace, he is to be escorted back to American airspace by MiG-23s. But in fact the two planes that show up are F-4 Phantoms. When the "MiG" fires a missile, you see a completely different plane. Best I can tell, that is not a MiG either.