Trivia

To cut costs, the same cave and doorway set used for Dr. Tobor's laboratory on the planet Theros, was slightly re-dressed to become the entrance to the doctor's underground freezing chamber beneath his laboratory on Earth.

The entire cast of the film is male. Not one female character can be found.

This was the first film (and the only serial) based on a television series.

To distinguish this theatrical version from the black-and-white TV series on which it was based, various scenes were originally printed in a process called "Cine-Color," a gimmick that basically used colored filters to tint black-and-white footage in red or green. Some existant prints are still in "Cine-Color," while others are entirely in black-and-white.

The theatrical posters featured artwork by Hollywood poster artist and commercial illustrator Glenn Cravath.