Revealing mistake: When he's speaking to Demetrius, Azor turns his back to the camera, and the zipper in his costume is visible.
Revealing mistake: During the initial dive the hydroplane on the sail (conning tower) is pointing upwards. During a later dive the hydroplane is pointing downwards. Wouldn't one position cause the submarine to surface?
Revealing mistake: In the shots taken from above, on the scene where Mallory and Stavros are climbing the cliff under hard rain, the rain falls over the back of them, not over his head. Reveals that this scene was taken in horizontal position over the floor. Not taken in vertical position.
Revealing mistake: When the prisoners commandeer the balloon and proceed to take flight, you can see a television antenna on one of the buildings in the background. (00:07:20 - 00:08:00)
Revealing mistake: At the opening of the film as the pirate ship passes left to right the flags are blowing in the opposite direction of the ship's movement and the sails keep blowing back although the ship keeps moving forward. Notice the large amount of churning water at the ship's rudder indicating that the boat is powered by a motor.
Revealing mistake: If you watch closely when the prisoner hits Jake with the shovel you can see the shovel bend as if it was rubber.
Revealing mistake: The sea creature Gorgo is paraded through the streets of London on a flatbed tractor trailer, and an off-screen American newsman announces the monster's arrival at Battersea Park, where it will be exhibited at Dorkin's Circus. The announcer introduces the creature's owners as they step from their motorcade, saying, "And our own Mr. Dorkin, of Dorkin's Circus, in the checkered suit." Problem is, Mr. Dorkin is wearing a plain gray flannel suit. Closeup shots of Mr. Dorkin over the next 40 seconds reveal that the suit is not checkered, not plaid, not striped, not patterned in any way at all. It's simply a plain gray suit. Apparently, the announcer's pre-recorded lines were never modified after changes were made in costuming. (00:34:05 - 00:35:00)
Revealing mistake: At the beginning of the movie, Talua is depicted as an isolated island in the South Pacific. Several shots show other islands in the movie. Many segments were shot in Hawaii (Maui) and you could see the Island of Hawaii in the distance.
Revealing mistake: The Son of Hercules brings to the nearby village the old man that died on the beach. You can see the 'corpse' move his arm to assist Mark Forest as he dismounts him from the horse.
Suggested correction: You must have been watching a poor-quality copy of the movie. In the HD version available on Amazon, the checkered pattern is visible, although it is subtle. Frankly, it probably would not be visible on a television broadcast of the time.
I watched it in HD purchased from Amazon Prime on a large high-definition screen. No checkered suit.
Charles Austin Miller
You may need to adjust your settings. It is especially visible in the interview scene. The suit definitely has a checkered pattern of various shades of gray. Again, it is subtle, but definitely visible.
You may need to check your imagination.
Charles Austin Miller