Other mistake: During "Cool," there's a shot where they're doing a sort of knee turn, and you can see Tucker Smith in the background spinning too many times (you can see him start to stick out his arms to stop himself). (01:58:20)
Other mistake: At the beginning of the film a bomber is crashing. As this is happening another bomber is stationary in the sky.
Other mistake: When the girls leave camp, if you look closely it is obvious that one of the girls (the one in the distance) is a double who does not look like Susan / Sharon at all.
Other mistake: When they are in the trench the other sub fires two torpedoes at them. The captain calls for right full rudder. They then show an underwater show of the sub turning left. After two more torpedoes are fired the captain orders left full rudder and they show the same underwater shot of the sub turning left.
Other mistake: When they're roping the mustangs, the "stallion" doesn't have the genitals of a stallion.
Other mistake: After the Cid dies and is propped up on his horse to try to fool the enemy into thinking that he still lives, he leads his army out of the fortress and attacks the offenders. Just after he comes out of the gates the horse stops and there is a shot of the Cid on his horse being almost silhouetted against the sun. If you watch carefully you will see Charlton Hestons' head move slightly and look towards the direction of the enemy.Even though the horse turns slightly under him the Cid's' head keeps looking in their direction. Obviously this would be impossible if he was dead, and even more so when you remember that his body was supposed to have been tied tightly to a support so that he would sit upright when on top of the horse.
Other mistake: The puppies apparently can't see when Lucky puts his head in front of the TV. The first time we see him do this, he is barely covering anything, but the puppies claim they can't see.
Other mistake: When Fats makes the 7 ball after Eddie's safe play, you see the cue ball flying into the pocket before the camera changes shots.
Other mistake: When the parent monster is just about to enter Piccadilly square, for a brief moment a view of a bus is shown. The writing on the bus is reversed.
Other mistake: The giant medallions that Pilate takes from a chest and then places on the pillar of the Temple do not bear close inspection as images of Tiberius, for some reason the name Augustus is lettered along with abbreviations not easily discerned as what was then used. The image behind Pilate when he is in court is similarly inauthentic but I would think that no-one but an exacting numismatist would even notice this if it is indeed such a major mistake.
Other mistake: When Regret, Jake, Pilar and her father are escaping from the Comanchero village, there's a close up of Jake (Wayne) in the back of the wagon shooting a rifle. The scene shows him shooting left-handed. It's a reverse print. Look at his "right" hand in the scene. He has a ring on his "right" hand ring finger. A few moments later, setting the wagon canvas afire trailing out the back of the wagon and shooting right handed, the ring is on his left hand as it is in the rest of the movie.
Other mistake: Just before Miss M sees the murder on the passing train, there is a shot of the express train overtaking hers. At the relative speeds, the express would have passed her window in 4 seconds, but she sees the murder for nearly 14 seconds.
Other mistake: Brian Keith sneaks into an Indian encampment at night while they are sleeping. In order to stampede their horses, he rapidly fires the one and only six-shooter revolver he has into the air...eight times.