Michael Caine said in a television interview that the only reason he did this movie was to earn enough money to put a down payment on a new garage he was having built.
The "Mandro" comic strip artwork seen in this movie was drawn and designed by real-life Marvel Comics artist Barry Windsor-Smith of "Conan the Barbarian" fame. Oliver Stone co-wrote Conan der Barbar (1982).
Writer and director Oliver Stone initially wanted Jon Voight to play the role of Jonathan, but was turned down by him. Christopher Walken and Dustin Hoffman also declined the role.
Apparently, after this movie, writer and director Oliver Stone and Sir Michael Caine became good friends, though Caine has never appeared in any of Stone's movies since this one.
One of Sir Michael Caine's notorious "paycheck movies", alongside Ashanti (1979), Der tödliche Schwarm (1978), Der weiße Hai IV - Die Abrechnung (1987), Freibeuter des Todes (1980), Schuld daran ist Rio (1984), and Jagd auf die Poseidon (1979).