Continuity mistake: Notice Marty's hair in the scene when he's playing "Johnny B. Goode." It's quite larger than when he says, some seconds later, "I guess that you're not ready for it yet." That's because when he says that, it's a recycled shot from the original BTTF, whereas most shots showing he's playing the guitar are newly made for BTTF2. However, Marty's hair is considerably longer in the new shots.
Continuity mistake: When Marty (the Marty wearing the dark clothing) is at the dance and the Marty of 1955 is on stage is about to sing Johnny B. Goode, you can hear the 1955 Marty saying "this is a blues riff in B, watch for the changes and try to keep up" through the microphone. Yet in the original, Marty looks away from the mike when he says this and is unamplified. The quote is different as well. He says "this is a blues riff in B, watch for the changes and try to keep up" in part I, but in part 2 he says "this is a blues riff in B, watch me for the changes and keep up, OK?" (01:24:25)
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.moviedude345
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.Jon Sandys
Biff: Go ahead, kid. Jump. A suicide will be nice and neat.
Marty: What if I don't?
Biff: [raising gun] Lead poisoning.
Marty: What about the police, Biff? They're gonna match up the bullet with that gun.
Biff: Kid, I own the police. Besides, they couldn't match up the bullet that killed your old man.
Marty: You son of a...
[Biff pulls back on the gun's hammer.]
Biff: Suppose it's poetic justice. Two McFlys with the same gun.
Question: Has anyone an idea about what kind of car is this one which almost hits Marty McFly Jr. as he runs out from Cafe 80's? For me it looks like Renault or Mazda, but I'm not sure, though I I can swear it must be some future descendant of the really existing nowadays car. Does anyone recognize any other familiar car in future vehicles? :).