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: Dick Jones brags (admits?) to Robocop, "I had to kill Bob Morton because he made a mistake. Now, it's time to erase that mistake" while Robocop is crouched on the ground, looking away from him from across the room. In the playback, Jones is facing the camera as though it were videotaped or filmed in a studio. (01:10:50 - 01:35:10)
Revealing mistake: Mac and Dillon go after the Predator. The Predator is sitting in a tree, and Mac points him out to Dillon. They both agree that they see it and take position. Mac crawls underneath the alien and is killed by his laser. The Predator then sees Dillon and lasers his arm off. Dillon's arm falls to the ground with the gun firing. Quickly Dillon turns and reaches for the machine gun around his neck. When he turns you clearly see his bloody right stump and his right arm sticking out the bottom of his jacket. [Note: As far as I can work out, this has been cunningly edited out of the UK DVD version].
Plot hole: Necros had absolutely no way of knowing that Bond and Saunders had arranged to meet at the cafe when they did, and wouldn't have had anywhere near enough time to track them down and set up his elaborate booby trap. Saunders only suggested the meeting place and time a few hours earlier, and it was kept strictly between him and Bond. The scene in Tangier where Whittaker tells Necros to kill another British agent takes place on the same day Bond arrived in Vienna; meaning that Necros got from Tangier to Vienna (a 5 hour-plus flight), tracked down Saunders, acquired the materials to booby trap the cafe doors (or had planned this ahead of time - unlikely) and set the trap up well in advance of he and Bond getting to the fairground. There was nowhere near enough time for all of that to happen without Necros having psychic knowledge of Saunders' movements.
Continuity mistake: In the opening scene, Gunnery Sgt. Hartman is making his speech and passes by Privates Cowboy and Joker on his way to the other side of the barracks. On his way he passes Private Pyle standing to the right of Private Joker. Later in the scene, when he rushes over to confront Private Joker and then moves on to Private Cowboy and then Private Pyle, Private Pyle is on the left of Private Joker. (00:02:00)
Revealing mistake: When Jack is hanging out of the truck you can see him standing on the hood of the car which Lydia is driving. At some points we get camera view from the back seat of the car. In some angles the mirror inside the car disappear. This is to prevent us from seeing the camera. (01:04:15)Mortug
Continuity mistake: In the car chase scene, the escaped convict and police are exchanging gun fire between cars. In the different shots of the police car, the bullet holes in the windshield appear and disappear several times. Also, when three shots have been fired at the police car there are four bullet holes in the windshield.
Other mistake: When Joe (The American Ninja) pushes the girl out of the moving truck, one sees the stuntMAN (playing a girl) mis-time the fall and land on a large clump of rock and dirt, after which, before the scene cuts, we see the stuntman curl over in pain. Obviously a very painful fall for the stuntman and a very very funny scene for the viewers.
Continuity mistake: When the two cops pull the stripper over, their car stops in the middle of the road. When Beck and Gallagher pass them later, however, their car is closer to the pavement. Their car moves yet again when Beck looks back at them out of his window. Also notice that three headlights are now on, including one that the stripper blew out. (00:51:30)Daz