Woody Strode and Henry Silva's characters later served as inspirations for Vincent Vega (John Travolta) and Jules Winnfield (Samuel L. Jackson) in Pulp Fiction (1994).
Second part of Fernando Di Leo's "Milieu Trilogy" also including Caliber 9 (1972) and The Boss (1973).
Because there were at least three different nationalities in the cast (Italian, German, American), the actual on-set dialogue for the majority of the shoot was in English. This is obvious if you watch the English-language dub; dialogue will sync up to the actors lips in most scenes, whereas they won't in the Italian and German versions.
German Import DVD has a Super-8mm Version (German language only), as a special feature on the disc.