This series was conceived as a sequel to the original 1950s classic movie. In several episodes, the character of Sylvia Van Buren appears, played by the original actress, and in one episode several characters go back through time to the time of the original movie.
Originally, Paramount had conceived the series not as a sequel or for television, but a feature remake of The War of the Worlds (1953) with George A. Romero slated to direct.
Three of the first season episodes were credited with pen names: "The Walls of Jericho", Forrest van Buren; "The Good Samaritan", Sylvia Clayton; and "Epiphany", Sylvia van Buren. The names were taken from the two main characters of the film, Clayton Forrester and Sylvia van Buren.
Originally, for season two, the Morthren deity, the Eternal, was to be called the Immortal (presumably to tie in with the "To Life Immortal" exchange of the Mor-Tax in the first season) and was going to speak in English.
At the beginning of the first airing of the first episode there was a brief sequence of clips from the 1953 movie with narration over it. The very last shot is a black and white image of a small boy standing in the wrecked Los Angeles from the end of the movie: the young Harrison Blackwood. This sequence was never shown again.
In her room at the Whitewood Sanitarium, Sylvia van Buren has a picture of Dr. Clayton Forrester by her bed.