Question: What happened to the original timeline to cause such a dramatic change in Marty's mom? In the original timeline, Marty's mom was 'born a nun' as Marty described her to Jennifer. But when Marty goes back to 1955, Lorraine is a drinking, smoking, parking with boys kind of girl. In the original timeline, what would have made it to where Lorraine thinks it's inappropriate for a girl to make advances on a boy? She seems to already be a boy chaser before Marty even gets there.
Question: What is the principal's problem? Why is he taking it out on a 17 year old?
Question: I have seen a different ending to this film. Every now and then when it airs on TV the movie ends with Doc in 1955, standing at the site where Marty just went back to 1985, and then Marty comes running up to him and says "I'm back" (or something similar). I seem to remember that this is the standard ending to the second film. Why is it occasionally used to end the first one?
Question: In the "first timeline", Marty's father is a loser. He has never hit Biff. Marty goes to the past, and when he's going to 1985, he says that to Doc. He returns to the "new" 1985, where his father is successful, and he has hit Biff. He sees himself going to 1955, and that Marty is about to do everything that Marty did in the movie. But here's a question: that Marty lives in the "second timeline", where his father has hit Biff. Why then, in the past, he would say that his father has never hit Biff in his whole life?
Question: At the beginning of the movie, the brother is a loser who works at Burger King. At the end, he wears a suit and work at an office. As a presumably successful business man, wouldn't he have moved out of his parents' house?
Question: In the scene where Marty is being chased around Twin Pines mall by the Libyans why is Marty driving straight towards the 1hr Photo Booth? I'm assuming he doesn't realise the time circuits were on, as he accidentally engaged them when changing gear. If he DID know, why drive 88+ mph knowing you don't have enough plutonium to get back from 1955? (00:30:00)
Question: Doesn't anybody think that when the Star Wars movies were released, that the name of the enemy, Darth Vader, would get George McFly a little suspicious? After all, he had to have remembered the name of the spirit that "came down to him from planet Vulcan" since it is on the cover of his book at the end.
Question: When Biff and his gang are first chasing Marty on the skateboard in 1955, Marty escapes by grabbing the tailgate of a passing pickup truck which tows him around the corner. The gang jumps into Biff's convertible to continue the pursuit, and Biff's convertible actually has a rear-end collision with the pickup truck, barely missing Marty. How is it that the truck driver doesn't even react to all this insane activity and the rear-end collision? Rather than stopping and demanding an explanation, the truck driver continues away from the scene without even slowing down.