When John Lithgow enters the Prison Cell with Jesse Ventura (WWF) the picture on the wall is of Vince McMahon President of the WWF who Ventura worked side by side with for years as a ringside commentator.
Denzel Washington worked out for three hours a day, six days a week for four months so as not to look out of shape for his shirtless scenes.
John Lithgow almost never blinks during this film. He wore a contact lens to give the impression that his Earl T. Blake character had a glass eye.
The fight scene in the prison cafeteria between John Lithgow and Jesse Ventura recreates the final duel from Russell Mulcahy's earlier film Highlander. There are multiple visual references, including the use of swords, the foley effects, the back-lit windows, and the camera angles, including the famous tracking shot of the camera rolling along the floor.
SPOILER: The date on the camcorder time index (when Styles arrested Blake) reveals the year to be 1983. Which means by the end of the film (1991) - the incarceration, escape, and Styles' children growing older; 7 and a half years roughly passed.
SPOILER: While the prison doctor is distracted by stitching Blake, Kim switches Jesse's medical and dental records. This revealed Blake and Kim had no intention of escaping with Jesse alive.