- Recycled Set: Sets are reused from Troll. The director was specifically asked to come up with a story that would largely take place in an apartment building because the studio wanted to get more use out of those sets.
- Troubled Production: Hoo boy! Klaus Kinski's antics were so bad that the director made a documentary about them. Prior to filming, the actor allegedly threw a fit over the wardrobe that had been picked out for him, and subsequently went out and bought his own clothes (charging them to the film and keeping them himself afterwards). On set, Kinski clashed severely with other actors and crew members. By the third day of filming, Kinski had started six fistfights and caused the film to fall significantly behind schedule. Schmoeller and the producers attempted to fire him, but Empire Pictures demanded that the bankable star remain. Aside from his combative behavior and bizarre demands (including an order that Schmoeller refrain from saying either "action" or "cut", essentially forcing him to film Kinski continually so he could start and end his scenes whenever he wished) he also refused to say any lines which he didn't like, to the point where, "Scenes were starting not to make sense because he would NOT say this or that line." Schmoeller resorted to Reverse Psychology, telling Kinski not to read certain lines, which seemed to work to some extent. Co-star Tane McClure later recalled that Schmoeller begged her to stay on set because Kinski (who she claims was "unfortunately, very interested in me") behaved better when she was around. Tensions reached the point of several crew members asking the director to, "Please kill Mr. Kinski"a request that became the title of Schmoeller's later film about the experience.
- What Could Have Been: The original script was an anti-Vietnam war tale revolving around a returning vet who decides to re-create a prisoner-of-war camp in his attic. If filmed, this version probably wouldn't have had Klaus Kinski - the producer convinced the director/writer to change the villain into a Nazi (feeling the Vietnam war was still Too Soon) by saying he could get Klaus Kinski in the cast, so the second draft was specifically written with Kinski in mind.
Trivia / Crawlspace