Corrected entry: In the beginning scene, when Doc Brown sends his dog one minute into the future, a minute later, they see the DeLorean again. But the reality is that they wouldn't, because the car would have also still been a minute ahead of them.
Continuity mistake: When Marty arrives in 1955, he puts the DeLorean behind the sign, and walks into Hill Valley. When Marty and the 1955 Doc come back later, the DeLorean is facing the other way round to what it was at the beginning (you can tell because at the start Marty pushes the BACK of the DeLorean AWAY from the Lyon's Estates billboard, but when they come later, the FRONT is facing TOWARDS the billboard). (00:35:05 - 00:51:15)
Continuity mistake: In the scenes where Marty enters the Lyon estates, if you look close you can see a stop sign, but if you watch the next two movies the stop sign has been removed. (00:11:50)
Suggested correction: I watched the films and the stop sign is still present.
Corrected entry: At the beginning of the movie, when Lorraine is telling her children about the dance, she turned to George and said it was the same night as the terrible storm. At the courthouse, the storm was fierce - wind, thunder, and lightning. At the dance, however, it was a pleasant evening. No evidence of a storm whatsoever.
Correction: "Same night" doesn't mean "at the exact same time". The dance and the storm both happened the same evening.
Correction: The school is some distance away from the courthouse, and the storm simply hadn't arrived there yet.
Corrected entry: When Lorraine follows Marty back to Doc's in 1955 and Doc goes to answer the door, he says to Marty (before opening it) that it's his mum. Lorraine must have heard them through the door yet she never questions it.
Correction: Two possible reasons she never asks about it. First, she simply did not hear him. You're assuming she did, but there's no evidence of it. Second, asking questions would be tantamount to admitting to eavesdropping. It's rude to eavesdrop and so Lorraine would hardly give herself away by asking questions about something she wasn't supposed to have heard in the first place, and which would have sounded nonsensical anyway.
Correction: Besides, even if she did hear him, so what? She knew she obviously wasn't "Calvin's" mum. She would have assumed his mum looked like her and Doc mistakenly thought that was who was at the door. But if she still decided to question it, I just gave an explanation that they would have used.
Corrected entry: When George walks in to Lou's, he orders a chocolate milk. How could Lou have made a chocolate milk in less than three seconds?
Correction: George is a regular, so it's possible Lou knew what he wanted. I've walked into bars and before I can sit down, my beer of choice is sitting in front of me.
Correction: Some soda shops have milk machines (I had one at the cafeteria in the dorms at college), one side is regular milk, the other is chocolate. Lou probably made the batch of chocolate milk that morning, and all he had to do was push a lever and fill the glass.
Corrected entry: On the DVD version, in the scene where Doc gets shot and then later reveals to Marty that he was wearing a bullet proof vest. A vest does not work in the way shown in the movie. It doesn't repel bullets (as shown in the "impact points" in the vest he displays), it absorbs them. Read how a vest works from howstuffworks dot com and you'll see what I mean. In addition, it looks like he is wearing only a Threat Level 2a class vest. An AK47 or similar weapon with a 7.62mm round would go clean through the vest, through Doc, and out the other side thus killing him and ending the story. The only style of vest that can withstand that sort of impact is a Threat Level 3 class vest (the style that specialized units in the military wear). This style is very bulky and is extremely difficult to conceal like Doc did. In addition, it has a ceramic plate in it which would have shattered upon the first impact and failed to protect against multiple impacts from that kind of weapon, and definitely not show "impact points" of twisted metal.
Correction: Doc is a brilliant scientist as well as an inventor. He had the time and the ability to invent his own special material that works like no other material known to man. If he can invent a time machine, I'm sure a bulletproof material would be easy for him.
As he stated in 1955, none of his inventions had ever worked. When he heard about and was shown the Delorean, he was amazed because it worked. I don't think that he would have been able to invent a jacket that repels bullets that great.
He is still a brilliant inventor/engineer that eventually makes the DeLorean run on bio-fuel and makes a train fly. Surely he can invent himself a vest.
Unless he is super paranoid I don't think he thought he would be shot.
Correction: After 30 years it's possible for him to invent the vest. Also, from what I see, the vest hasn't repelled the rounds, as we can see where they've hit as the rounds have impacted the vest.
Corrected entry: Between scenes Marty's shoes change, e.g. in the skateboard chase scene he is wearing black converse shoes, but when he is in the time machine travelling back to 1985 he is wearing white Nike trainers.
Correction: Not a mistake. After Marty says "Yeah, I can spend a week in 1955." Doc says "first, we have to get you out of those clothes" - this is so Marty blended in with current fashions of the 50's. When Marty is going back to 1985, he claims that he isn't going back in his 50's clothes - "you think I'm going back in those clothes?.", or something to that effect. It was all done to make Marty less suspicious to the people around him.
Correction: That's not how it works, at least in this movie. Einstein jumped a minute ahead instantly, Doc and Marty "catch up" after a minute of their normal time. Einstein isn't permanently a minute ahead of everyone else on the planet forever.