George Pal wanted to film the novel's sequel, "After Worlds Collide," which depicted the struggle of human survivors on the alien planet. However, the failure of his film Conquest of Space (1955), and the declining health of uncredited executive producer Burgess Meredith, damaged his relationship with Paramount, and the sequel was never made.
There is a shot toward the end of a group of people sitting around a country store listening to the radio. Among them the little boy and dog later rescued by helicopter. The same shot shows up in The War of the Worlds (1953)
When the effects of Zyra are shown there is a shot of a volcano erupting where the side of the peak falls outward. This same shot was used in other George Pal films, including The Time Machine (1960) and Atlantis: The Lost Continent (1961).
Screenwriter Bruce Joel Rubin saw this film as a ten-year-old, and has cited it as "the beginning of the emergence of philosophy" in his life. In The Dialogue: An Interview with Screenwriter Bruce Joel Rubin (2007), he explains that right after he and a boyhood friend saw the film, they spent hours discussing the end of the world. Rubin mentions this memory while explaining that Steven Spielberg approached him to do the screenplay for a remake of "When Worlds Collide," and that it eventually evolved into Deep Impact (1998), with Rubin credited as one of its two writers.