During a screening, Roger Corman actually smacked an audience member on the head for laughing at the film. When Roger left the theater, the guy he punched poured soda all over his head from the balcony.
Approximately six minutes of footage was removed from the original pre-release assembly on orders of producer Roger Corman, who was angered by witnessing a test screening audience laughing uproariously at some of the comedic passages that were subsequently removed.
The effects footage from the initial space battle is all recycled from Roger Corman's Battle Beyond the Stars (1980).
The modular forms decorating the hallways of the research lab are hinged-lid Styrofoam sandwich boxes.
All releases of the film show the same 77-minute cut, which was released as "Forbidden World", including the theatrical prints. The 2010 DVD release includes the completely uncut version, originally titled "Mutant", on the bonus disc.
Susan Justin: The film's composer can be seen on screen as the character of Annie, albeit only in a picture.