One wonders if the people who make films like this really care if audiences like them or not.
So let's see...we've got a museum curator who gets a statue in the mail along with a request to do radiometric dating on it. If he were competent in the field he would send it back since radiometric dating is unlikely to produce a meaningful date on a manufactured metallic object. But he goes ahead and does it and somehow determines that the piece is from the future (5200 AD). Never mind that radiometric dating doesn't work like that and couldn't give a future date for anything. He also is told later that the piece is dangerously radioactive. Well, again, if he were competent at the radiochemistry needed for the dating, he would have found THAT out right away. But ANOTHER scientist has to tell him that after the fact.
The piece is the product of a scientist and his financial backer working alone in the Everglades. If everything that comes though the time machine is so hopelessly radioactive, why aren't they both dead, or at least very sick? If the statue is so dangerous, why do the scientists who produced it (and who know it's radioactive) leave their amazing discovery lying around, and don't notice when it turns up missing? And if the apparatus used for this time travel is so powerful that it screws up TVs, lights, and motorboat engines, how is it possible for the young backer to be using it without anyone else's knowledge? And why 5200 AD? Don't the scientists have any control over the time period they explore? What's so interesting about 5200 AD as opposed to other times? Why not a hundred years in the future, or a billion years for that matter? Why not go backward in time?
Nothing much happens in the middle of the movie so it branches out into desultory explorations of jealousy and voyeurism, only to drop these themes when it comes time for "science fiction" to rear its head again.
And then the Terror shows up - an ugly woman. Somebody's got some issues with women I think! She speaks Greek from a few letters on a Phi Beta Kappa key, then conveniently switches to modern English when that doesn't work. She can hypnotize you with her sparkly fingernails. Oh, yeh, and she can kill you and steal your face. Which she does to the lovely and talented Salome Jens (the only actor in this wretched mess to deliver a well-crafted performance). From here on the script backfills furiously in a hurried attempt to generate meaning in this meaningless heap of trash before the budget runs out.
Time travel is an enormously complicated plot device for a science fiction film; few have done it well. "Terror from the Year 5000" is not one of them. It tries to cover its obvious shortcomings in pointless and unexplained plot diversions.
But again, it's unlikely the makers cared. Thank God it didn't wreck Salome Jens' career at the outset.