Trivia: In an interview, the director stated that hoverboards were real, but they weren't on the market because parents didn't like the idea of floating children. He said this as a joke, but this didn't stop mass hysteria as thousands of kids went from store to store looking for hoverboards.
Trivia: When Doc and Marty arrive back in 1955 to stop the handover of the Almanac, there are 4 versions of the time machine in the area at that time - the one they just arrived in from the alternate 1985, the one Marty arrived in from the original 1985 in the first film, the one Biff arrived in from 2015 in the second film, and the one Doc buried in 1885 in the third film.
Trivia: Towards the beginning of the movie there is a close-up of the front window of Blast From the Past. If you look closely in the upper left hand corner you can see the jacket that Marty wore in the first movie. Also if you look on the right hand side you can see a Who Framed Roger Rabbit doll, another Robert Zemeckis film also starring Christopher Lloyd. There's also a Jaws video game. (00:12:28)
Trivia: Many people think Crispin Glover reprised his role as George McFly for part II, but it's a different actor who had facial prosthetics applied to look like Glover. These prosthetics were made from actual molds of Glover's face left over from part I. Glover never authorized his likeness to be used and sued. The Screen Actors Guild now has laws against "unauthorized mimicking" of other actors as a result of the lawsuit. Crispin Glover is listed in the credit for part II only as "archive footage"
Trivia: In the scene where the Doc of the future, hands the 3/4 wrench to the Doc of 1955, the Doc of 1955 is wearing the same two watches that the other Doc wears throughout the entire movie. This could actually happen if the Doc of 1955 kept the same two watches to wear throughout his life. It's still worth a look. (01:13:53)
Trivia: According to Robert Zemeckis, the kitchen scene with Michael J. Fox playing three characters simultaneously (middle-aged Marty McFly, his goofy son and bubble-headed daughter all sitting at the same table) was a nightmare to shoot. The characters required individual matte shots that were later spliced together into one scene, requiring many takes; so every visible object in the kitchen background had to remain perfectly stationary and consistent over several days of filming. Thinking ahead, Zemeckis ordered his property crew to hot-glue every single background object in the kitchen in-place, to prevent accidental movement. However, when they were well into filming the tricky scene, the studio was struck by an earthquake, which essentially destroyed the kitchen set, hot glue and all, requiring a rebuild and complete re-shoot.
Trivia: In Back to the Future II, Biff is watching the Clint Eastwood movie A Fistful of Dollars. If you have seen this, you know that at the end, Clint uses a piece of metal to stop all the shots from Ramon. In Back to the Future Part III Marty calls himself Clint Eastwood and at the end, he uses a piece of metal to keep himself from dying. (00:55:30)
Trivia: When Marty discovers that he is in an alternate Hill Valley, there was going to be a scene with him discovering that his sister Linda was a prostitute and his brother Dave a homeless drunk living on the streets. These scenes were scrapped as Wendie Jo Sperber, who played Linda, was pregnant at the time.