When this film won the Hugo Award for Best Dramatic Presentation, the award went to the writer(s) and director(s) (in this case, L.Q. Jones), as had been done for years before. However, Harlan Ellison, author of the original story who at the time had already won six Hugos, put up such a fuss at being left out that the Hugo committee eventually decided to include him. Unfortunately, there were no iconic Hugo Award rocket statues left, so the committee just gave him an extra base. With the two Hugos he would win after this, Ellison would claim to have won eight-and-a-half Hugos, with this being the half.
The dog Blood sustained no injuries during filming. The scenes depicting him limping were created by placing a rubber band around his paw.
One of the reasons the film now enjoys cult status is because of its blackly comic last line. Ironically, Harlan Ellison hated this and actively campaigned to have it removed.
At a science-fiction convention, there was a pre-release screening of this film. At the end, when writer Harlan Ellison came onstage and invited comments, the most common one was that the portion of the movie taking place in The Underground was slow-moving (a polite way of saying "boring"). Ellison was very defensive about this and responded to the effect that The Underground was a boring, stultifying place and the movie was intended to convey that. The audience did not find this to be a satisfying answer.
Ray Manzarek (as Ray Manzarec), keyboardist from The Doors, was also among those credited for the score. Tim McIntire sang the main theme. Bolivian composer Jaime Mendoza-Nava provided the music for the "Topeka" underground segment.