Continuity: During the car chase involving the car driven by the Chinese guy, Murtaugh, and the mobile home, the two cars slide against each other and the right wing mirror on Murtaugh's car is completely wrecked. Once the two cars are separated the wing mirror has miraculously repaired itself. The left wing mirror also does a disappearing / reappearing trick.

Deliberate "mistake": During the big gun battle right before the last fight scene, Riggs is shown driving a forklift, and knocking over some barrels on top of Jet Li's character. When the forklift does the 180 degree turn, you can CLEARLY see that it is not Mel Gibson, but is an Asian stunt man.  He must have been the only stunt man on the set who could drive a forklift.

Continuity: In the scene where Mel Gibson And Danny Glover drive a car through an office you see Mel floor the car in one shot, and when they show a view of the car you can see the brake lights are on.

Continuity: Near the end when Butters is shot, Danny Glover is holding Butters' head up, you can see Glover's tie down on his chest and in the next scene it's over his shoulder, and then the tie is back on his chest in the next scene.

Continuity: In the scene near the end of the film when Murtaugh shoots at Jet Li and mistakenly kills the last of the four fathers, you can clearly hear an empty shell casing hit the floor, although he is using a revolver, which do not spit out the empty shells as they are fired.

Continuity: At the end of the movie when Riggs, Murtaugh and the other two cops enter the garage where the Triad chief is buying the four fathers' freedom whe can clearly hear the hard rain outside, but the car that they're driving is completely dry - maybe they had a very big umbrella!

Continuity: When Riggs is on the table and jumps into the moving car, the table is run over by another car. A few seconds later you can clearly see the table still attatched to the plastic.

Continuity: When the car launches towards the office block you can clearly see the rollcage and missing passengers.

Continuity: More geographical problems: During the scene filmed on a supposed L.A. highway where Mel is on a table loosely connected to a semi, the Luxor hotel in Las Vegas is seen in the background.

Revealing: The shark Joe Pesci catches is unbelievably fake - you can even see the seams.

Continuity: In the scene where Mel Gibson throws the table leg at the man's car, the table leg makes a hole and the glass around cracks. Each time the camera focuses on the car the amount of glass that has cracked has changed.

Continuity: During the gunfight with the armored man, more and more bullet holes continue to appear on Riggs and Murtaugh's side of the car which is facing away from the armored man with the gun. And in one brief scene from the armored mans view, there are no bullet holes on the side of the car which he had fired at and hit several times.

Continuity: When Riggs suggests that Murtaugh take his clothes off to distract the gunman, Murtaugh's tie suddenly drops and his collar is undone. In the next shot his tie and collar are done up again.

Continuity: Right before the highway scene, the distant mountains are green and lush, but when they get onto the highway, the mountains become close and desert-like. This is because this scene was done on the empty, brand-new I-215 in Las Vegas.

Continuity: When Riggs is hanging off the roof and the others are trying to move a dumpster for him to drop into, the handcuffed Chinese waiter is trying to help. A shot from the top shows the waiter pushing the dumpster with his (outstretched) leg, but a split second later, a shot from the side, he has his back to the dumpster.

Continuity: After Mel shoots the human tank's napalm valve and he goes flying under the tanker truck, Gibson hops over the hood of the car he's behind. In the next shot he and Glover are running away from the falling tanker as if Mel had never moved.

Continuity: Near the beginning, when the tanker trailer is blown, you can see where each of the charges are placed the moment it blows as well as see the rear wheel of the tanker mechanically fold under.

Deliberate "mistake": When Riggs is chasing the guy on foot, you can clearly see it is a stunt double, who is also very apparent in other shots throughout the film.

Plot hole: When the armored guy is propelled under the tanker trailer, his backpack explodes. That blast can not have been large enough to lift the entire trailer through the air. The trailer never explodes itself, and if it did, the tank itself would have torn apart and the frame beneath would have stayed on the ground, pushed down by that blast above. (Oh, and there's no such "safety feature" that is intended to launch a trailer in the air in case of an accident.)

Revealing: When Riggs jumps from the car onto the house that's being moved, you can see when the stuntman replaces Mel Gibson. Look at his hair, it changes styles as he jumps.