The first science fiction film to be shot in three-strip Technicolor.
"Dr. Cyclops" was Albert Dekker's signature part, and virtually all of his obituaries mentioned the film.
Theatrically released in the USA with Me Feelins Is Hurt (1940) as the preceding cartoon in some locations.
Standing more the 6'6", director Ernest B. Schoedsack was very aware of his status as a giant among men. Some of his colleagues from that era suggest that the filmmaker's height may have motivated, at least unconsciously, his desire to approach the subject in his artistic endeavors. While many mad doctors were played by actors who were relatively modest in size, Albert Dekker (who had never before been associated with this genre) was selected for the role in part because of the similarity between his own bulky build and that of the director.
Allen Fox as "Cab Driver" is in studio records/casting call lists for that role, but he did not appear or was not identifiable in the movie.