Continuity mistake: When Riggs is thrown off the tow truck and rolls across the ground the Ryder truck that was just overtaken by the tow truck disappears and reappears between shots. (00:37:25)
Continuity mistake: When the surfboard crashes into the tow-truck cabin the driver is gone. (00:37:35)
Continuity mistake: During a chase scene involving Murtaugh's station wagon and a flatbed tow truck, the hotel waiter shoots at Riggs through the truck's rear window. In this series of shots, notice how Riggs is swinging by a chrome handle on the passenger's side - which wasn't there during the gunpoint hijack shot just moments ago. (00:39:30 - 00:40:45)
Continuity mistake: When firing his gun at Riggs through the flatbed's rear window, the hotel waiter's shooting hand switches from left to right between shots. (00:40:50)
Visible crew/equipment: When the hotel waiter aims his gun and takes a second shot at Riggs through the flatbed's rear window, a camera truck makes a brief appearance on the right. (00:40:50)
Continuity mistake: When the hotel waiter shoots at Riggs through the flatbed tow truck's rear window, Riggs manages to cling to a handle on the passenger's side and avoid being hit. However, immediately before the waiter runs out of bullets and throws down his gun, look sharp and you'll see how all of the window's busted glass is once again intact, like new. (00:40:50)
Revealing mistake: When the small car is launched into the air, the underside is plainly visible, showing no normal working parts like a suspension or drivetrain. It has a flat pan bottom with a square-tube support structure to make it very light for its flight and to retain it shape. (Director's Cut.) (00:42:40)
Visible crew/equipment: There's a shadow of a crew member moving across the lighted trees when Rudd asks Rita in front of the embassy whether she understood what had happened today. (00:44:10)
Continuity mistake: In the drive-thru scene you can see that the right half of the grill and both right headlights on the wagon are gone. When they pull up at Roger's in the scene where Leo gets kidnapped the right headlight is working. (00:45:20 - 01:03:15)
Visible crew/equipment: When Riggs first starts shadowing Rudd, he cuts off Rudd's car with his truck. They go to the close up shot of Riggs and when he drives away you can see in the reflection of the trucks window, the PANAV on the hood of the Panavision camera. (00:48:35)
Continuity mistake: While he's on the toilet, Murtaugh is wearing a flak jacket that disappears for one shot while he is getting instructions from the bomb squad leader. (00:54:25)
Continuity mistake: When the bathroom explodes, from one angle we see the toilet come sailing out over the roof of a police truck parked at the front of the house. While the angles make it a bit tricky to judge, there's a definite leftward trajectory. We then cut to a closeup of Murtaugh's car, and the toilet lands on it as if it was flying to the right. Even if the angles are misleading, in the first shot the police truck and other cars are parked to the right of the exploding window. In the shot of Roger's car he's also parked to the right, but without all the cars visible around it which there should be. (00:57:15)
Suggested correction: The toilet is flying straight out and straight towards the car - you can see this from the perspective of the interior of the car prior to the toilet becoming visible. Next the toilet is flying towards the area in front of the police van, not over it. And the car is parked in front of the van. When we see the car again, the van and other police cars are out of frame, so they can't be seen.
The mistake is valid. When we see the toilet flying, it's moving to the viewer's left, but when it hits the car, it's moving to the viewer's right now. Even if in the first shot, with the angle of the camera, the toilet is flying straight, it doesn't hit the car straight on. And he's not saying the toilet sails over the roof, but that you can see the toilet in the background is above the roof of the van in the foreground and that's moving over it (from right to left).
Deliberate mistake: It's surely an intended joke, but that the toilet not only survived the explosion but also the landing in one piece is very unrealistic. (00:57:15)
Revealing mistake: In Rudd's office Riggs stops the first attacker with a good head butt. He misses the guy's face and just touches the chest a little, but in the next shot the guy is dramatically holding his nose. (01:01:45)
Continuity mistake: When Rika comes to Riggs' trailer he offers her a chair, and she sits down twice in different camera angles. (01:07:50)
Suggested correction: This is too subtle to be called a mistake - she's in the process of sitting when she's facing the camera, the shot changes to behind her and she's seen finishing her settling into the chair - this could just as well be her making a natural adjustment to her sitting position. It's not an obvious mistake by any means.
Continuity mistake: When Rika sits down outside of Riggs' place, the front of the trailer is half shaded by the sunroof. When the camera angle changes the shade is gone, and it's much brighter. (01:07:50)
Suggested correction: This entry is only half right - the "sunroof" or awning is visible from both camera angles, though it's true that the sun is lower and is lighting more under the awning when the camera moves inside the trailer.
Continuity mistake: After inviting Rika to his trailer, Riggs walks inside and opens his fridge to get a beer. On top of the TV nearby is a VCR. Flash forward to the helicopter attack scene where Rika and Riggs are about to escape through Sam's doggy door. Here you can see there's no longer any VCR on the TV set. (01:14:20 - 01:24:15)
Continuity mistake: In the scene where Murtaugh is shooting his attackers with the nail gun the walls are apparently covered with super plastic. How is it that the plastic sheeting is light enough for the bad guy to punch through, but is able to support the weight of his corpse by a single nail when Murtaugh shoots him through the plastic? Wouldn't the plastic tear and drop the body to the floor? (01:15:45)
Revealing mistake: When Riggs and Rika make love a safety blanket separates the crucial areas. (01:16:25)
Continuity mistake: After Murtaugh confirms the Alba Varden is a ship, one of Rudd's henchmen enters the house armed with a knife. Moments later when they're struggling by the hobby room's blueprint table, Murtaugh grabs the nail gun and shoots him in the forehead. Now right here, you can notice the sound of a knife being thrown to the floor as he reaches for his head. But when the henchman is up against the unhinged doors, he's once again holding a knife in his right hand. (01:21:55)
