another element of realism in the film is the superimposing of the voices in german and spanish, as chillon explained: "those documentaries had only one soundtrack, that's the reason why when they were dubbed, the original soundtrack had to be kept in and the translated narration had to be superimposed." both voices are heard on the soundtrack, "with a distinctive classic tone from the 1950s sci-fi films with characteristic melodies and effects from that era."