Revealing mistake: Riggs handcuffs himself to the depressed businessman. They jump off the building but they're not handcuffed to each other anymore. They used plastic cuffs which could separate during the stunt in case anything went wrong. They break just as they jump, so they grab each other's hands to stay in contact. After they land the cuffs are attached again. (00:31:00)
Continuity mistake: In the scene just after the jumper, Murtaugh pulls Riggs into a room and asks Riggs if he wants to die. He hands Riggs his pistol. When Riggs puts the pistol to his temple you can see and hear him cocking the hammer. After some arguing about the positioning of the gun, Riggs then puts the barrel unter his chin. While he's pulling the trigger the camera goes to a close-up of the pistol and shows the hammer pulling back, as he squeezes the trigger. (00:34:40)
Continuity mistake: There is a scene where Riggs and Murtaugh are driving in a car, and the column shifter keeps going from park to drive and back. (00:37:00)
Continuity mistake: When Riggs and Murtaugh are driving to the house in Beverly Hills to shoot the guy in the pool, Riggs is lighting a cigarette and then Murtaugh says "You're not gonna smoke in the car." Riggs answers "Yes, but I'm gonna roll down the window." In the previous shot you can see that the window is already rolled down. (00:38:20)
Other mistake: Just after Danny Glover's shot the guy by the pool, Mel Gibson goes to handle the two girls. We hear all the exchanges between him and them offscreen, such as "don't move or I'll break your arms", etc., ending with him saying "Got 'em", and we hear a pair of handcuffs click. When we see the girls, they're either side of a tree, with the camera-side cuffs on a wrist each. But we only heard one set of cuffs (all while off-screen, so there's no reason we wouldn't have heard another set go on), and with only one set on, there's nothing to stop them running away. (00:40:20)
Continuity mistake: As Riggs exits the car, he takes the cigarette out of his mouth. The camera angle chages to show him standing outside the car, handling his pistol, and the cigarette is back in his mouth, with no time to put it there and the audio indicates the shots are consecutive time. (00:45:20)
Continuity mistake: When Murtaugh is about to find the envelope with the porno tape he takes a can of beer from the fridge and opens it. When he is sitting down, the same can of beer is opened again audibly. (00:49:25)
Continuity mistake: Just as his wife is about to smack Murtaugh's butt at the oven, a small ladder is at the right, angled to face Murtaugh's position. As the shot changes to get a bit closer, the ladder is suddenly more parallel with the cabinetry. (00:50:25)
Continuity mistake: While working out the case at the shooting range, Murtaugh only fires one shot, and Riggs fires 9 (offscreen shots during their continuous conversation are noticeably quieter, from other shooters). When they reel in the targets, Murtaugh's target has 6 holes, and Riggs' has 14 or 15. (00:52:00)
Continuity mistake: At the shooting range, just after saying "That's very thin", Riggs has his arms outstretched, semi-aiming his gun. Cut to a two-shot, and he's got his arms into his body. (00:52:55)
Visible crew/equipment: When Riggs and Murtaugh compare their targets, a crew member sneaks up behind Riggs and disappears in the next shot. (00:53:30)
Continuity mistake: When Murtaugh clips on another target it's crumpled at the side. When it comes back after he has shot, it's clipped on straight. (00:55:00)
Continuity mistake: The kids in front of Dixie's house change positions between shots when they shout after Riggs and Murtaugh, like the one with the baseball cap who sits up. Furthermore, this little guy can't help glimpsing at the camera for a second. (00:55:40)
Visible crew/equipment: When Riggs walks up to Dixie's house the camera is reflected in his sunglasses. (00:55:45)
Continuity mistake: When Riggs and Murtaugh walk toward Dixie's house before it blows up, they're wearing large clear glasses, almost like the safety glasses they were wearing at the firing range. After the house blows up they aren't wearing them anymore or even seen taking them off. (00:56:20)
Continuity mistake: The lawn in front of Dixie's house turns completely into naked dry soil at the end of the scene, even at places where it should not be really affected by the extinguishing operations. (00:57:25)
Plot hole: One of the children is a witness that saw the man that planted the bomb in Dixie's house. He is said by a policeman to have been playing 'under the porch' and was close enough to make-out the Special Forces tatoo on the bomber's arm. Problem is, Dixie's house had no porch of any kind, and any other home's porch would've placed him too far to see such a small tatoo so confidently. (00:57:40)
Suggested correction: The rear of Dixie's house is never shown. The house could conceivably have a back porch the kid could have been playing under and the killer could have used the back door.
Continuity mistake: When Hunsaker's shot, his eggnog gets all over his tie and shirt. When the camera angle cuts to Murtaugh's reaction, Hunsaker's shirt and tie are clean and there is no eggnog pouring from the container. Also there is no hole of any kind in the glass door behind him in which the bullet made. (01:04:00)
Suggested correction: You can see the eggnog on his shirt and tie. As Murtaugh is kneeling next to Hunsacker it is very visible.
Continuity mistake: Just before Hunsaker's shot, he's standing right in front of the window. When it cuts to a wider shot, he's suddenly a foot or two further left. (01:04:00)
Revealing mistake: When Riggs walks up to the "Irish-Chinese" hooker it's raining quite hard, but not on him. (01:05:35)
