Although "The Green Slime" was released in the U.S. as a 90 minute version, director Kinji Fukasaku and his editor prepared a much more tightly edited 77 minute version (called "Gamma III: Big Military Space Operation") for release in Japan. This "Japanese" version eliminates the Robert Horton/Richard Jaeckel/Luciana Paluzzi relationship triangle, and is much more "militaristic" in tone. Several scenes are edited differently, additional alternate music cues are used (which are less "sci-fi" sounding than the "Amercian" version), and the rock and roll theme song is omitted entirely (replaced by a military march theme). The ending before the credit roll has additional scenes inserted with Paluzzi and Jaeckel, which change the tone of the ending from optimistic to downbeat.