Flip-Flop of God: The director on whether the events of the film were real or all in Quaid's mind. In the commentary, Schwarzenegger leans more to it actually happening, whereas Verhoeven leans more towards it being the ego-trip.
Technology Marches On: Although the film is set in 2084, an advertisement is seen for Fuji Film despite the fact that by the early 2000s, analog photography has been made all-but-obsolete by digital photography.
Troubled Production: The Mexico City shoot was considered a nightmare for most of the cast and crew. Many cast and crew members got sick at one point from contaminated water (the only major members of the production who didn't get sick were Schwarzenegger, who had remembered being sick during the Mexico shoot of Predator and took special precautions, and producer Ronald Shusett, who would give himself B12 shots each day to avoid illness) and the air was so polluted that Schwarzenegger recalled having trouble breathing on most days.