Corrected entry: When Doc is explaining to Marty about the ravine and the plan to hit 88 mph, you can quickly see Clara in the background, before they introduce her.
Corrected entry: Near the end, when Needles challenges Marty to a street race, the smartest thing for Marty to have done was nothing. By speeding away in reverse, he could have just as easily hit another car behind him, with the subsequent chain of events leading, more or less, to the future that Jennifer witnessed in 2015.
Correction: Well, Marty didn't know about that future anyway, as Jennifer never told him she found out what caused his failure. Him reversing is a lot more like a definite change in character for Marty, rather than an attempt to change the future. That's what the scene was about. Next to that, he quickly spins the car around without coming to any intersection, so no immediate danger of running into someone.
Corrected entry: When Marty returns to 1985, an overhead shot shows the Eastwood Ravine. The camera pans over to ground level and the ravine is gone. The tracks are on the ground and there is no bridge. (01:42:15)
Correction: We just jump forwards a few seconds - the bridge is visible in the background, we just didn't watch him rolling the entire way into town.
Corrected entry: When Clara realizes her mistake, that Doc may have told her the truth, and races to catch the train on horseback, a "Kentucky Thoroughbred" at the speed of 45mph could not catch the train at the speeds the colored logs were burning off.
Correction: The colored logs didn't begin firing off until Clara reached the train. In fact, the first one fired off just as she grabbed onto the rear handrail, causing her to be jerked horizontally.
Corrected entry: When doc picks out clothes for Marty to wear to the old west, Marty asks if they are authentic, so Doc says "sure, haven't you ever seen a western?" Considering Doc is supposedly a genius and the old west is his favorite historical era (he himself said it was his favorite era in part 2) he should know that Hollywood's version of old west clothing and the reality of it are two different things. Doc should know better than to base his knowledge on Hollywood films.
Corrected entry: When Seamus McFly goes to comfort his crying baby son William, we can see that he is a very affectionate father. This was practically unheard of in the 19th century. Children were routinely beaten for even the smallest infractions at the time, it was the norm. Since William was only an infant, I doubt he would be beaten, but his father would not be so kind towards him either. His attitude would be more like "shut up kid, what are you crying about now?". The whole concept of being affectionate towards one's children is more of a 20th century idea.
Correction: And yet people are different, no matter the age or cultural norms. Some people are just nicer than others, it has nothing to do with some preconceived notion of how societal norms were for any given time. When my father was a child, it was acceptable to give a wife a backhand if she "got out of line", but he never did.
Correction: It was not unheard of in 1885. Showing affection to children became a trend as early as the 1850s.
Corrected entry: Why would Doc label the toy car "time machine" when they both knew what it was? Having the car marked like that would only make sense for Clara to see it when she arrives at the livery so she would assume that Doc was telling the truth when he told her he was from the future. Since Marty and Doc wanted to minimize their true identities and their association with the future, they should have covered the train set up, just in case they failed in their attempt and/or had to come back.
Correction: This is a question, not a mistake. We already know from the first film that Doc is meticulous (apologizing for the model not being to scale).
Corrected entry: What are Great Plains Indians doing in California?
Correction: The cavalry are chasing them so they may be on the run. The US Army pursued some Native groups deep into Mexico, so it's hardly unlikely for them to have fled this far.
Corrected entry: When Doc and Marty locate the time machine in the mine/cave in 1955, the door/entrance to the mine cave is too small to have been used in 1885 to get the time machine into the mine cave. Others have said that Doc had the intelligence and time to disassemble the car/time machine, carry the parts in and re-assemble it inside the mine/cave. The problem with this is that while many parts (engine, doors etc.) could be disassembled, the body and frame can only be disassembled so much, they would still be too large to get through the door. Doc would have had to cut them up, carry them in, and then weld them back together. There were no signs of a welding process (weld bead) on the roof, which is part of the one-piece body. Since the body is stainless steel, the welds could not be sanded down and painted over, and there is no paint.
Correction: We only see ONE entrance to the mine. There could have been several more that were big enough to fit the DeLorean. Also, there most certainly would have been many large entrances back in 1885, when the mine would have actually been in use.
Corrected entry: In the letter the Doc sends to Marty in 1955 telling him where to find the time machine and telling him not to come back to 1885 to rescue him, he says he has met a wonderful woman and is thinking of settling down with her. When Marty goes back to 1885 the day after the letter was sent, the Doc has not met Clara yet and does not appear to have any other female attachments.
Correction: Doc does talk about settling down in the era, but makes no mention of meeting a woman in his letter.
Corrected entry: When Marty and Doc first discover the gravestone in 1955, watch closely as Marty puts his hand on it. It wobbles slightly, revealing that it's a prop made of lighter material as opposed to actual stone.
Corrected entry: When Jules, Marty's son, comes out of the train at the end, look at his expression. He looks like he is about to burst out laughing.
Correction: First of all, he's Doc's son, not Marty's. And second, there is no reason why the kid should not be laughing. Maybe he is excited about travelling through time, maybe he finds the 1980's surroundings funny, or maybe his brother had just told him a joke. There are a thousand possible explanations to this.
Corrected entry: When Doc and Marty are in the blacksmith shop, Doc reads the picture tombstone: Shot in the BACK for a matter of $80. Even Buford emphasises this in the previous scene; "one day you gonna get a bullet in your back". However, in the festival scene when Buford is about to shoot Doc, Doc is facing FORWARD. If Marty had not been there to stop the bullet with the frisbee, Doc would have been shot in the chest, not the back. (00:36:00 - 00:58:45)
Correction: You're not thinking fourth dimensionally. If Marty had not gone back in time, he and Doc wouldn't have saved Clara. If Clara hadn't been at the dance, Doc may well have not been at the dance. Biff would then have shot him somewhere else and in the back. Marty being there messes up the whole time continuum. Doc even mentions something along the lines of Buford being early during that scene.
In the original timeline both Doc and Clara were at the dance. Without Marty being there Doc would have been shot in the back. When Tannen says "told you to watch your back smithy," that's what prompted Doc to reply that he felt early since he knew he wouldn't be dead until the 7th. Basically in the original timeline, Tannen shot Doc in the back at the dance and he bled out until finally dying on Monday the 7th.
Corrected entry: When Doc puts a buffer on the train, it has tires in it. No-one had cars so where would he get the tires from?
Correction: They are the tyres from the Delorean.
Corrected entry: In the scene where Doc explains to Marty the idea of pushing the DeLorean across the bridge, Marty points out that the bridge is not completed yet (in 1885). Doc says that Marty is just not thinking 4th dimensionally, and once they return to 1985, the bridge is complete, safe and still in use. Unfortunately, the whole idea of returning to the exact same point in space, but a different time, is fundamentally flawed. If the DeLorean was to return to the same point in SPACE, only 100 years later, it would have to account not only for the completion of the bridge, but to all of the other changes to the physical environment. For example, in 100 years, the North American continent would have moved because of continental drift, the Earth would have rotated on its axis, so that point in space would no longer be Hill Vally, CA; the whole planet is revolving around the sun, therefore, the planet Earth wouldn't be in that exact point in SPACE, the sun is revolving around the galaxy, the galaxy moves through the universe, and on and on. Anyway, the DeLorean couldn't have shown up on the completed bridge 100 years later because Earth is moving through space in several different ways.
Correction: This entire arguement assumes that the time machine does not maintain or compensate for momentum. Since every time they travel through time they end up in the same location we can assume Doc designed the machine to compensate for plate tectonics. planetary orbit, and galactic drift.
Corrected entry: Okay, we're going to get a bit deep here. Doc and Marty found Doc's grave in 1955. Doc sends Marty back to 1885 to rescue Doc. Now.....remember....all hinges around the image on the picture. Once the grave stone is broken in the fight with Mad Dog Tannen the image of the grave disappears in the photo. Wouldn't the picture disappear too? No grave in 1885 means no grave in 1955 which means no reason to take a picture in the first place. But then again....once the grave is broken then there would have been no grave in 1955 for Doc to see. Therefore he would have never sent Marty back in the first place. HENCE...once the grave was broken....the timeline is fixed and Doc of 1885 would live happily ever after with Clara, Doc of 1955 would just work on getting Marty home, and Marty would have disappeared from the 1885 timeline and things would have continued from when Doc and Marty are digging out the old DeLorean. Told you it was deep.
Correction: Marty took the picture of the grave BEFORE he went back to 1885 and changed the past, so there's no logical reason why the picture itself would disappear. Obviously, he wouldn't take a picture of nothing, but he had already taken the picture, which is why only the grave disappears.
Correction: For all we know, Marty could have been thinking of going back and convincing Doc to return to 1985 anyway, despite being told not to. The gravestone was probably a way of further motivating Marty's idea, but he could have wanted to go back in the first place after realising that he had no other choice.
Corrected entry: At the end of the movie, when the new time machine built into a steam locomotive begins flying and departing, the train signals are still running and the barrier crossings are still down. The train signals should have stopped once the flying time machine locomotive was off the tracks.
Correction: Train signals generally stop once the end of the train is a good distance away from the road where the signals sit, by sensors. In the film, the train is too close to the road and by lifting up in the air, the sensor to stop the signals were never reached by the train.
Corrected entry: It would have been a lot easier for Doc to construct a rudimentary rocket using gunpowder as the propellant than the highly unlikely solution that he ended up doing. He could have attached two pipes, either side of the car. Gunpowder from bullets, shotgun cartridges etc. Wouldn't even need the railroad wheel conversion although I reckon would be better on rails than a dirt road.
Correction: A rudimentary rocket is in no way a better solution to their problem. It would be highly unstable and unlikely to produce enough thrust. A rocket used to accelerate a car to 88mph would need a much more suitable fuel than gunpowder.
Corrected entry: In the scene where Doc is at the saloon, after Clara doesn't believe him, he orders a drink. The bartender then says "I don't know about that, remember what happened on the Fourth of July?" Doc arrived in 1885 on September 1st. He wasn't there on the Fourth of July.
Correction: Doc got zapped back to Jan 1st, 1885. In his letter at the beginning of BTTF 3 he mentions that he had been living for 8 months in 1885. So it is possible that he was there on the Fourth of July.
Corrected entry: At the beginning, after Doc sent Marty back to the future, you can see Marty hiding behind the cars before he runs out.
Correction: Of course he was hiding behind the cars. He had to prevent his past self from seeing him. He then comes out when he's sure that the past self has gone.
Correction: Clara is waiting at the train station for Doc to meet her which is why she's seen.