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 Gunslinger's pixellated POV.
There were several minor injures during filming. During a shootout scene a piece of wadding from a blank cartridge struck Yul Brynner in the eye, scratching his cornea and leaving him unable to wear his light reflecting contacts without his injured eye turning red and tearing up, so shooting had to be maneuvered to allow time for his eye to heal. And during the scene where James Brolin's character was bitten by a rattlesnake, while the milked rattler was attached to Brolin's arm, he was bitten by the teeth on the snakes lower jaw, despite wearing padding on his arm made of leather and cotton.
Director / screenwriter Michael Crichton re-edited first cut of the movie because he was depressed by how long and boring it was. Scenes which were deleted from the rough cut include the bank robbery and sales room sequences, hovercraft with passengers flying above the desert in the beginning, additional and longer dialogue scenes, more scenes with robots going crazy and killing guests including a scene where one guest is tied down to a rack and is killed when his arms are pulled out, longer chase scene with Gunslinger chasing Peter, Gunslinger cleaning his face with water after Peter throws acid on him. In Crichton's assembly cut there was also a different ending which included a fight between Gunslinger and Peter (which was deleted because it seemed like it was staged and foolish) and an alternate death scene of Gunslinger where he is killed with the same rack that was used by one of the other robots to kill one of the guests in previously mentioned deleted scene.
Michael Crichton would later use the similar plot line about an amusement park that goes horribly wrong and the attractions malfunctioning for his novel "Jurassic Park", which would become a hit film (Jurassic Park (1993)) 20 years later.