The Time Machine (1960) - 3 major mistakes

Continuity: The Morlocks aren't affected by the light from metal in fusion in their foundry but they recoil from the light of a match.

Plot hole: In 1966 when George is about to return to his machine and the atomic bombs (or whatever) go off, George just barely gets out of there before the lava from a nearby volcano cooks him alive. Two plot holes here. One is that in the short time it takes George to walk a few meters to his machine, a volcano explodes and the lava reaches him. Thats very speedy lava..especially considering there were no mountains near George's house. Secondly when the lava approaches, it is just flowing along the ground like normal. But when it reaches George, it splashes around him like a broken water tank. That lava can certainly defy gravity.

Continuity: When the time traveler is first starting to travel in time, the sun moves across the window from left to right, indicating that the window faces south. When night arrives, however, the view is of the stars moving right to left, indicating that the window is facing north.