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 where the girl jumps to her death from the balcony, it shows her hitting the car towards the right halfway onto the windshield. Then in the next shot, it shows her lying right in the middle of the roof of the car. (00:04:05)
Continuity mistake: When Mel Gibson is talking about the special bullet, kept as the suicide special, he describes it as a hollow point - to do the job right. When he shows the bullet it is a full metal jacket.
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: The wet patches on the sleeve of Nick's T-shirt change when the family surprises Murtaugh in the bathtub. Actually, when they carried the B-day cake in, the T-shirt should have been dry in the first place as the water battle started only later. (00:04:55)
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.
Revealing mistake: When the car crashes into the bus and lands on its top, you can see a big square hole cut out of the car's underside. (01:30:35)
Continuity mistake: At the end, when Riggs is at his wife's grave, it's supposedly raining. In one shot you see Riggs' hair is dripping wet, and when you see him bend down to put the flowers on the grave in the next shot, his hair is dry, and in the next shot it's wet again. (01:44:00)
Continuity mistake: During the scene where the General is escaping in the car and Murtaugh shoots the driver. When the car is hit by the bus on the avenue you can see part of the device that makes the car flip over and roll away from the crash. (01:30:35)
Continuity mistake: In the scene where "the General" and his driver were fleeing down the alley, the driver is shot. The general takes control of the wheel and carries on driving, but the car is in park... (01:34:25)
Continuity mistake: The Christmas illumination on the balcony of Amanda Hunsaker's hotel room is arranged in three different ways: In the first shot, before she takes drugs, it is attached to the side of the railing. When she steps out, the lights are hanging about 10 inches below the railing, like they are later when Murtaugh searches her room. And when she climbs up to jump the bulbs are directly hanging down from the railing. (00:02:40)
Continuity mistake: Before Amanda jumps she climbs up some steps onto the railing without holding on to anything. However, in none of the earlier shots (or later when Murtaugh searches the room) there isn't anything on the balcony that could have served that purpose. (00:03:30)
Revealing mistake: When Murtaugh's car is going towards the meeting point, there's some extra dust coming from the right, caused by crew members. (01:12:55)
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: 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: 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)
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: When coked-up Amanda first looks down from the balcony, we see the ground from her vantage point. Were she to jump from this location, she would land on the huge awning below (the curved dark area). If she put real effort into jumping forward to clear the awning (and she didn't), she'd land just to the right of the lighted sidewalk, onto the grass. And if she were an olympic long-jumper and not high on cocaine, she might have landed on the red or black car parked at the curb. Under no circumstances could she have landed on the gray car, well to her left - yet she does. (00:03:05)
Continuity mistake: (Director's Cut) As Murtagh later states (and Riggs does not correct him), Riggs' 9mm pistol has a 15 round clip and holds one more 'in the pipe' (barrel), yet when he took out the sniper earlier, he fired at least 19 rounds in a single, rapid sequence. (00:13:30 - 00:27:45)
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)
