Director Piers Haggard said in a 2003 interview for 'Fangoria' magazine, "I took over that at very short notice. Tobe Hooper had been directing it and they had stopped for whatever reason. It hadn't been working. I did see some of his stuff and it didn't look particularly good plus he also had some sort of nervous breakdown or something. So anyway they stopped shooting and offered it to me. Unfortunately I had commitments, I had some commercials to shoot. But anyway I took it over with barely ten days of preparation - which shows. It doesn't become my picture, it's a bit inbetween . . . [actor Oliver Reed was] scary at first because he was always testing you all the time. Difficult but not as difficult as Klaus Kinski. Because Oliver [Reed] actually had a sense of humour. I was rather fond of him; he could be tricky but he was quite warm really. He just played games and was rather macho and so on. Klaus Kinski was very cold. The main problem with the film was that the two didn't get on and they fought like cats. Kinski of course is a fabulous film actor and he's good in the part, the part suits him very well. They were both well cast but it was a very unhappy film. I think Klaus was the problem but then Oliver spent half the movie just trying to rub him up, pulling his leg all the way. There were shouting matches because Oliver just wouldn't let up. None of this is about art. All the things that you're trying to concentrate on tend to slip. So it was not a happy period."
In the home release commentary director Piers Haggard states that stars Oliver Reed and Klaus Kinski hated each other during production. Reed constantly provoked and pranked Kinski until he would lose his temper.
Klaus Kinski chose this movie over an offer to appear in Steven Spielberg's Raiders of the Lost Ark (1981) because he was offered more money. Kinski said in his autobiography "All I Need Is Love: A Memoir" aka "Kinski Uncut: The Autobiography of Klaus Kinski" (1988, 1996) that he thought the screenplay for Raiders was "moronically shitty."
Piers Haggard replaced Tobe Hooper as director. At a party at Elaine's Restaurant in Manhattan celebrating the film's release, Klaus Kinski boasted how he and other members of the cast and crew had ganged up on Hooper a couple of weeks into the shoot to get him replaced.