Goofs...
Here's a couple that have always annoyed the hell out of me:
When George first presses ahead at a faster speed, and we're watching the sky... sun, moon, and stars rotating... the sun and moon are going in one direction, and the stars are going in the opposite direction... which of course, is impossible. All celestial bodies travel in the same perceived direction, because it is a product of the Earth's diurnal rotational motion of West, to East. (sloppy work)... but then, audiences of the 1960s were not at all sophisticated, nor was it percieved that anyone would notice, nor care.
Another issue:
When George is encased by the mountain in darkness, he strikes a match to read the display on the control panel of the Time Machine... yet- the day/month/year displays are rear-lit, and holding any type of light to the front, would tend to make the displays more difficult to read.
Where, I grew up watching this film as one of my favorites... I just wish that George Pal had put a little more effort into producing a less-flawed film... at least as much as his photographic effects. Of course, he may have been the victim of sobriety.