Trivia

Director Harry Bromley Davenport stated in an interview on the DVD release that he looks back on the film with embarrassment, saying that the bizarre atmosphere of the film was completely unintentional and that there is no deeper, symbolic meaning to the strange, random events that happen, because he and his co-writers were very high on drugs while writing the script and would often throw in whatever random ideas popped into their heads or thought would be neat, such as the panther scene and the toy soldier coming to life. Davenport has also said that despite being unhappy with the film, he is somewhat proud of its reputation for being a disgusting and bleak horror movie.

The creature that attacks the woman in the cottage was played by a mime they hired to crawl on his back.

Even though the plot involves extraterrestrials, the creatures in this film are at no point referred to as aliens. Some fans like thinking of them as Lovecraftian-type beings. It's also never said they come from another planet, so it's possible they come from another dimension.

Film debut of Maryam d'Abo.

The film was often incorrectly listed as a UK video nasty though it was never officially listed among the original 72 titles, although it was included in the supplementary Section 3 video nasties list