Visible crew/equipment: When Bond tries to get the golden bullet from the belly dancer named Saheeda, some angry gangsters enter her dressing room. As they start destroying the place, you can see the crew in the mirror on the dressing table very clearly after one of the bad guys is knocked into it, nudging it out of position.
Revealing mistake: In the shot where Bond rams the long tail boat of the karate experts, you can see that the boat is split in two pieces and the bow is already sinking before the collision.
Continuity mistake: The AMC Matador stops as the AMC Hornet X races by on the cross-street. As the Matador halts, we see it has a proper door mirror. In a close-up of Scaramanga driving, we can just see the hole in the door where the now-missing mirror was mounted (on the VHS full-frame, we can see the remote cable hanging from the hole and the base of the mirror swinging as the mirror hangs out of view).
Continuity mistake: When the AMC Matador arrives in the hangar and begins attaching the jet plane equipment, we see a bracket welded to the lower rear quarter panel, just behind the door. The wing supports swing down to attach at this point on both sides of the car, yet these brackets were not on the car in any prior shot.
Visible crew/equipment: James Bond is backing up the red AMC Hornet X, preparing to jump the wooden bridge. Sheriff J.W. Pepper says, "What the hell you doing now, boy?" and then you can see a studio light and a crewmember in the reflection of the right rear passenger window.
Visible crew/equipment: During the car chase scene where Bond is driving the red AMC Hornet X, Sheriff J.W. Pepper says, "The nearest bridge is two miles back." Look at the rear window and you'll see the elbow of a crewmember on the roof of the car appear into view.
Plot hole: When Bond and Scaramanga are dueling, Bond has no tie or jacket on. After Bond drops his gun and gives his hiding place away, he somehow has the time to not only crawl back onto the staging, but to move the wax replica of himself, and also to put on the dummy's jacket and necktie.
Character mistake: James Bond states that the man that fell in the liquid helium would raise the temperature. Since humans have a body temperature of only 98.6 degrees Fahrenheit, falling into a tank of liquid helium at -456 degrees would bring his body down to the same temperature as the surrounding helium in no more than five seconds.
Visible crew/equipment: In the scene where Bond walks in on Scaramanga's girl in the shower, you can easily see a crewman in a mirror as the camera pans.
Continuity mistake: When we first meet Francisco Scaramanga we see that he has a third nipple which is just above his left. The next time we see him he is lying on a beach chair showing the left of him. If you look carefully you will notice that there is no third nipple.
Factual error: The film's car chase takes place in Thailand, where vehicles are right-hand-drive (RHD) and travel on the left side of the road (as in England and Australia). Yet the American Motors (AMC) cars in the chase (the red Hornet X, gold Matador coupe and several Matador sedan police cars, all 1974-models) are all left-hand-drive cars. Scaramanga's car can be excused as something he specifically imported for himself, but the Hornet is 'borrowed' from a fictitious AMC dealership (none existed outside the USA) and the small amount of AMC vehicles sold outside the USA were shipped disassembled to various companies that reassembled them and sold them under their own company names (AMI in Australia, Karmann in Germany, etc). Companies such as these, in RHD nations, had to modify the cars to RHD themselves in order to be allowed to sell them 'locally'. So the Hornet would have been at a non-AMC dealership, and would have been RHD, as would the fleet of police cars. Naturally, this 'error' was created by AMC's promotional deal with the filmmakers to use AMC cars in order to improve US sales to the US filmgoers.
Factual error: James Bond comes out of the "Bottoms Up" topless bar and down to the waterfront. He jumps on a boat and tells the boatman to take him to "Kowloon side". In fact, Bottoms Up is on the Kowloon side of Hong Kong harbour, so he's already there. If he wanted to cross the harbour, he should have asked for "Hong Kong side".
Audio problem: In the teaser we see the hitman load his gun when he gets ready to kill Scaramanga. When Scaramanga walks into the room, the hitman aims for him. The gun makes a loading sound. A loaded gun does not make a sound when you aim it - and why would he have unloaded the gun while waiting for his victim? When you load the gun, the hammer is back and the gun is ready to fire. No further actions are necessary. And a professional hitman does not wait to turn off the safety on his gun until his victim has arrived.
Visible crew/equipment: As Bond slides himself past the curtain in the hotel room, just before placing the champagne on a table, in the lower right corner of the picture you can see three points of reflection of light on a glass or chrome object on the board (an ashtray?). The left one of these suddenly turns dark, indicating some movement behind the camera. Bond cannot have caused that as there is no light behind him, all light comes from the right and from behind.
Continuity mistake: As Scaramanga turns the laser gun towards the plane you can see that the gun never points at the plane, while he turns it and when he shoots. The perspective shows that the gun never points closer to the plan than some 30 - 40 m behind it.
Continuity mistake: At the start, when the gangster is preparing for the showdown with Scaramanga, there is a rope hanging with a knot in it, however, when Scaramanga comes in the knot in the rope has been tied.
Revealing mistake: Scaramanga's jet-car fires up its roof-mounted jet engine and begins to roll forward in the hangar. Despite the fact that we hear the turbine whining loudly at increasing RPMs, the flimsy tan sheeting hanging in front of the jet intake is not sucked in, or even disturbed at all by the air flow.