Factual error: When the Victorian astronauts are on the moon they are dressed in deep sea diving suits - without gloves.
Continuity mistake: While avoiding the glowing meteoroid, they decide to fire their jets to push them into a higher orbit. In a couple of scenes they go up but a third one has them going back down.
Continuity mistake: About 25 minutes into the film, Vincent Price puts two vampire bodies into the back of his station wagon. Viewed from the open rear door, the woman is on the right side face up and the man is on the left side face down, and he drives off to the pit. In the next scene, he parks the car at the pit and when he goes to unload the bodies, the woman is now on the left side face down and the man is one the right side face up. For people who have died and then been killed again, they sure did move around a lot in the back of that car.
Suggested correction: Is this really a mistake? H G Wells wrote "The First Men In The Moon" over 1900-1901 before the invention of the aeroplane, when space travel was still a fantasy. By 1964 Yuri Gagarin and Valentina Tereshkova had flown into outer space, so the makers of this film knew what sort of equipment would be needed if you really wanted to make a trip to the moon. And this film shows astronauts in suits copied from those worn by actual astronauts. But the idea of the original book, and this 1964 film, was that a (very) eccentric English Victorian scientist led an expedition to the Moon. So, surely, if Victorian Englishmen and Englishwomen went to the Moon, they would have used the technology available at the time. Beside that, when they reach the Moon they find it is inhabited. Even in 1900 astronomers knew there was no life on the Moon. I don't think this film was meant to be taken too seriously, and that when they made the film they deliberately dressed the cast in deep sea diving suits as a joke.
Rob Halliday