Revealing mistake: During the fight scene in the belly dancer's room, Bond spins the bald guy around to avoid being hit by a chair. When the bald guy gets hit in the back with the chair, you can see a large rectangle of padding under his jacket.
Revealing mistake: At the start of the film when the gangster lands on Scaramanga's island, and enters Scaramanga's fun house, he encounters a scene where some dummies of Al Capone and some other gangsters come out of an area guns blazing... With the first burst of machine gun fire, the dummy "blinks"... (00:05:25)
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. (00:59:30)
Revealing mistake: When Knick-Knack pulls the money from the dead gentleman who Scaramanga kills in the game before opening credits, you can see a "wax figure" of James Bond pointing his gun. But he is moving, and not standing completely still like a wax character/mannequin would. (00:07:55)
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. (01:29:05)