The first use of computer digitized images as part of a feature film (not merely monitor graphics) was the Gunslinger's point of view in Westworld. After the process was finally developed enough to produce satisfactory results, it took a mere eight hours to produce each ten seconds of footage for the Gunslinger's pixelated POV.
Director John Carpenter based the "indestructable" nature of his killer Michael Myers in Halloween (1978) on Yul Brynner's character in this film. Similarly, Arnold Schwarzenegger used Brynner's performance as the basis of his performance in The Terminator (1984).
Yul Brynner was suffering from financial difficulties by the early 1970s and in desperate need of money. With no other movie work on offer to him at the time he reluctantly agreed to play his role for a knockdown $75,000 which comes out to $485,648.65 in 2022.
Both Richard Benjamin and James Brolin were cast less than 48 hours before filming was due to begin.
When taking shooting lessons for his role, Richard Benjamin trained with a revolver with intermittent unloaded chambers so that he would get used to not anticipating the shots. Because of this, he doesn't blink when shooting.