Continuity mistake: After Riggs' Houdini-esque underwater escape, he makes his way to the pair of hitmen on the docks above. One of them gets thrown through a car door's glass window, and Riggs uses that same door to bash his head repeatedly. As Riggs is dealing the blows, pay attention during the close-up shots and you'll see reflections in a brand new piece of glass. (01:32:50)
Other mistake: Roger intercepts Riggs and blocks the path of his truck. After agreeing to a plan, we hear Riggs driving off. But his original path is still blocked and we don't see him pass behind Murtagh, so he must have reversed direction (which seems unlikely since he's continuing his drive to the same destination). But for his truck to have headed the other way, he'd have to turn it around first, but we hear it simply drive off. (01:35:40)
Factual error: When Riggs and Murtaugh make the car go through the container door it has only a few meters to accelerate. It would have never been able to gain enough speed to leave the container almost horizontally. (01:36:15)
Continuity mistake: In the final shoot-out Riggs shoots a guy who is looking down a ladder. We see about four exit wounds on his back, but no injury in front, neither later when Murtaugh takes a look at the corpse. (01:37:30)
Continuity mistake: In the fight scene toward the end of the film between Riggs and the guy who killed his wife and Rika, look carefully at the watch Riggs is wearing - it moves from one arm to the other in close-up as Riggs forces the guy to stab himself. (01:38:35)
Factual error: In the scene where Riggs drops the container, there were only two buttons on the control. I've never seen a hoist with a drop button, just an up and down and they are pretty slow. (01:39:25)
Other mistake: When Riggs kills the guy who murdered his wife by dropping that cargo crate on him it's obvious the crate has no bottom and it falls around him, not least because the body's height doesn't change as the crate falls, there's no sign of impact or crushing, he just stays perfectly upright as it hits the ground. (01:39:25)
Suggested correction: This is simply not a mistake - we obviously know that the filmmakers didn't really crush an actor, but there's no visible clue of the SFX "deception."
Continuity mistake: In the final scene where Riggs is in Murtaugh's arms the side shots show blood all over the left side of Riggs' face but the straight shots there is just a little on his left cheek and chin. (01:41:55)
Visible crew/equipment: On the Alba Varden, just before Riggs gets hit in the leg by a knife, a shadow from the camera, as it moves backwards, can be seen on the orange container to the right of screen. (01:42:30)
Plot hole: Riggs and Murtagh send the car flying out of the container, pushing the money out as it goes. Ignoring that the car couldn't possibly force the sealed container doors open, even without having the obstacle of pallets loaded with money in the way, the car actually explodes in mid air for no reason. (Director's Cut.) (01:44:35)
Continuity mistake: At the end when the shootout on the Alba Varden has finished, as police cars are shown driving over the bridge while Murtaugh attends to the wounded Riggs in the cargo area, the sky is pitch dark. Two minutes later when the credits are rolling, the sky is now much lighter. (01:46:40 - 01:49:00)
Continuity mistake: When Pieter throws a knife at Riggs from offscreen, it sticks into his leg. Note that most of the blade is still visible. All things considered, the knife could have been able to penetrate maybe two, three inches into the skin (at best). But look closely in the following shot as well as subsequent shots where Pieter starts kicking Riggs in the face and you'll notice how the knife has managed to drive itself completely through and out the opposite side. Arguably the knife could be long enough and, with immense effort, this might be possible, but Pieter throwing a knife all the way through Riggs' thigh just seems absurd. (01:46:45)
Audio problem: In the scene where Leo explains how he launders the drug money and Roger says "You're a cheat", Leo says "Come on, everyone cheats a little, look at the pentagon." But when he says "look at the pentagon", it's dubbed in because the sound of his voice doesn't match his other dialogue, and if you read his lips it doesn't match either.
Continuity mistake: At the end of the movie, when Riggs is in the cargo area, a gunman shoots at him, he rolls and starts emptying the clip into him - you see the bullet holes in the gunman. But as Riggs is face to face with the gunman, the holes disappear.
Deliberate mistake: The way diplomatic immunity is depicted in the movie is extremely inaccurate. While technically a sufficiently ranking diplomat could perform the acts shown in the movie without being subject to arrest, their home government would be requested to turn the diplomats over for trial, or the diplomat would be declared persona non grata and expelled from the country. A drug smuggling ring and murdering multiple policemen is far, far more serious than actual crimes that diplomats have been expelled (or handed over for trial) for in the real world. Additionally, the consul general and his officers would not be considered diplomats. They would only have limited consular immunity with regards to "official acts" in the course of consular business.
Factual error: All vehicles sold in the U.S. since the 1950s have federally-mandated laminated windshields. When the surfboard crashes through the windshield of the truck, the windshield shatters like ordinary unlaminated glass.
Factual error: When Riggs and Murtaugh rappel from the container they have no gloves. Considering how fast they descended 20-30 feet, their hands would have suffered very bad rope burn.
Plot hole: During Riggs' last fight with Adolph, Adolph holds the knife in his own hand as Riggs forces him to stab himself very slowly. At any point, Adolph could simply have let the knife fall or just tilt down before that happened. Nothing Riggs is doing is making such impossible. "Locking" his wrist does not prevent him from letting go of the knife. It only prevents him flexing his wrist. And this guy is a trained killer, fighting for his life. Better to battle for control of the knife than just let it kill you.
Continuity mistake: Near the end of the car chase you see a shot of the station wagon Riggs and Murtaugh are riding in get held up by a couple of police cars. The hood is popped open. The shot changes to the BMW crashing into the store window and then back to the station wagon. The hood is down.
Continuity mistake: During the opening chase when Riggs is driving through the small gap on the bridge, as Murtaugh shouts, "Get off ya mother f***er", the car that is next to them goes from being right up against their car to a good 10 feet away between the 2 shots.
