Corrected entry: Towards the beginning, when Marty returns to 1985 and walks up to Biff's hotel he runs into the town drunk and refers to him as "Red." Red was the mayor in 1955, shown in the first movie when a campaign van is driving around the town square saying "Re-elect Mayor Red Wilson".
Correction: This is not trivia, this is part of the plot.
Correction: The names of the mayors are mixed up in this entry. The 1955 mayor was Red Thomas and the 1985 mayor was Goldie Wilson.
No that's the point. Red Thomas has fallen on very hard times in this alternate timeline 30 years later and has become the town drunk.
Bob Gale said this isn't true, the name was improvised.
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.
Suggested correction: Very unlikely for a family film, and needs to be supported by some evidence such as a published interview with a film principal. This is a ridiculous entry and should be removed.
There was, in fact, a deleted scene in which Marty comes across Dave, who has since become an alcoholic, in the town square. While it is true that Wendie Jo Sperber was pregnant and thus unavailable at the time the film was made, I've never heard of anything scripted about Linda having turned to prostitution.
If you have the DVD or the Blu-Ray, watch the movie with the Trivia Track on. It will confirm that Wendie was originally supposed to appear as her character Linda who had become a prostitute.
Corrected entry: We all know that Old Biff stole the time-machine, went back to 1955 and gave the book to himself. He also returned the time-machine to Marty and Doc. WHY? He actually gave them the ability to restore the past. Why didn't Old Biff just keep the time-machine?
Correction: Biff doesn't know how time travel works. Presumably, he assumed that if he were to go back to the future, he'd end up in the alternate future he had just created (which would make sense) and become the 'rich' Biff.
Correction: Character choices are not mistakes.
Continuity mistake: At the beginning of the movie when Doc smashes through the trash cans, his glasses are not on. In the shot where he steps out of the car they are.
Suggested correction: He put them on in between shots.
Correction: He actually says "Brett" - the joke being that Brett from the normal 1985 (the town drunk) is exactly the same in the alternate 1985. Hes the only one who hasn't changed, hence the way Marty says his name.