Question: Why does the storm end immediately after the clock tower is struck by lightning? This happens again in part 2 when the DeLorean gets struck by lightning. All of a sudden, the wind and lightning is gone.
Question: We see Biff groan in pain as he returns to 2015 with the stolen DeLorean. In a deleted scene we actually see Biff fade away as he is erased from existence by his actions. I assume this is because an alternate Biff now exists (or could have been killed) and so he is erased from time. If this happens to Biff, why doesn't this happen to Marty, Doc, and Jennifer? They too are replaced by alternate versions of themselves when they return and even before they return to 1985a. 1985a Biff even says in the film that Marty was in school in Switzerland, and Doc has been committed, so they too should fade away as Biff did, shouldn't they? I would say "time" was giving them time enough to correct things like in the 1st movie, but Biff faded away almost a soon as he arrived back in 2015a.
Question: During the chase scene, Marty jumps into the water at one end to avoid getting hit by Griff. A few seconds later Marty is out of the water at the other end and climbing up stairs. How did he get to the other end so quickly? Why is he climbing up the stairs after being in the water at the other end of the pond?
Question: When Marty and Doc arrive in the bad 1985, they learn that 1985 has changed and are told that alternate versions of themselves exist. Alternate Doc has been committed and alternate Marty is at a boarding school in Switzerland. Nice movie trick to keep them from running into their alternate selves. Question though, isn't the 1985 at the start of this movie also an alternate 1985? This too has been altered from the original 1985 as seen at the beginning of the first movie. So, where are the alternate Marty and Doc in the timeline when Marty's family is actually upper middle class? Since this is an alternate 1985 as well, where is "rich" Marty? Why didn't he bump into his other self, the Marty that owns the black pickup truck?
Question: In Biff's casino Marty is escaping Biff and his goons - he goes into the stairwell and jumps from one stair to another. What I don't understand is how this stairwell works as it seems to be double, with 2 sets of stairs ending up on the same floor parallel to each other, one on one end and one at another but on the same floor. Does this even make sense? Can anyone tell me why a big building would have 2 sets of stairs in 1 stairwell going parallel and end up on the same floors? Any special name for this type of stairwell perhaps? I can't find anything on it.
Question: At one point in the film Doc pulls out a case of "emergency money" he's collected from different time periods. When did he have the time to go to all those time periods? Marty went to 1955 and after getting back Doc went to 2015 before coming straight back again to get Marty to go to the future, so when did Doc have the time to go collecting all that money?
Question: When BTTF Part II was originally released in theaters, was the trailer for Part III part of the original released film, or was the trailer added in later when it was released on VHS like they did with "The be continued..." when Part I was released on VHS?
Question: Does anyone know why Marty takes a book of matches off of Biff's desk when Biff isn't looking? I know that the matches come in handy at the end of the film when he burns the sports almanac, but what was his original reason for swiping the matches? Unless he knew beforehand that he was going to have to burn the almanac.
Question: Why does Doc suddenly change his ideas (about time travel and not learning too much of your own future) in Part 2? In Part 1, he was determined not to learn too much about his own future, despite Marty trying to warn him that his life depended on it. But in Part 2, suddenly it's okay to bring Marty to the future and give him enough information to try to change the course of destiny for his son. Also, wouldn't it have just been easier to warn Marty about the accident he was going to have that caused his life to go so wrong to begin with? One would have to think that if Marty becomes successful and lives out an entirely different life, then maybe his son doesn't turn into such a wimp.
Question: In the scene where Marty's recently purchased sports almanac drops out of its plastic bag, Doc says that he did not invent the time machine for financial gain. In Back to the Future's first Twin Pines Mall scene, Doc says that he'll get to see who wins the next 25 World Series. Can we assume Doc would not have tried to profit from knowing those results in advance?