Corrected entry: When Biff and his gang crash through the windows of the clock tower with their hover boards, Marty goes to give his back to the little girl, but she says "keep it, I've got a pitball now" and shows him Biff's hover board. Only problem is it's still in the clock tower wreckage, attached to the other 3.
Corrected entry: When Marty goes to the cemetery, it says his dad was born in 1930 and died in 1973. If the Enchantment Under the Sea dance [George's senior prom] was in 1955, that would have made him 25 at the time.
Correction: I just saw that scene it clearly reads born in 1938, making him 17 in 1955.
Corrected entry: The cooling vents on the back of the DeLorean change between silver and black throughout the film. A clear example of this is the first landing scene of the DeLorean in the alley in 2015.
Corrected entry: When Marty's daughter answers the door she lets in Grandma Lorraine and Grampa George. Lorraine says that she brought pizza for everyone. Marlene says "who's going to eat all of that" and Grampa George says "I will." Yet, when the pizza is hydrated, Grampa George is not in the kitchen at the table or in any of the following house scenes.
Correction: Any number of explanations. Grandpa George could have been in the bathroom, for all we know.
Correction: He was to the side, off-camera. There's a deleted scene that shows this.
Corrected entry: The money ratio in 2015 seems incorrect. When Doc sends Marty into Cafe 80's he hands him a $50 for a Pepsi. In another scene when Marty is walking outside, Old Terry asks Marty for $100 to save the clock tower. Usually a soft drink would cost more than what a man waving a can would ask for. Then when old Biff gets out of the taxi, his total comes to $174.50. According to the price of a Pepsi, doesn't this taxi ride seem cheap?
Correction: Two things: the Pepsi/donation ratio isn't that odd; if you paid a dollar for a Pepsi, giving a couple of bucks to help a local landmark is pretty normal. The taxi fare only seems 'incorrect' compared to what we're used to now. Cab rides are expensive due to wages, gas prices, vehicle upkeep, and other expenses; perhaps they've found a way to keep those costs down.
Corrected entry: When the Doc gets hit by lightning and goes back in time, he's not going 88mph, which Marty had to do in the first movie.
Correction: According the director's commentary, when the DeLorean was hit by the lighting, it got sent into a tight, fast spin which brought the speed up to 88 mph. This is also the reason why the fire trails look like backward 9's; the car is spinning, so the fire trails can't be straight.
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.
Corrected entry: When Marty is trying to recover the future copy of the sports almanac from the office of Mr. Strickland, he sees that inside the almanac's cover is a dirty magazine. ("Oh La La"). After Strickland leaves the office, Marty tears the almanac cover off, crumples it up, and throws it on the ground, leaving it there. Later, at the dance, BTTF2 Marty is knocked down by a door that is thrown open by the BTTF1 Marty and Biff sees the, now intact with no crumpled cover, almanac inside Marty's leather jacket. Biff then takes it, never replacing the Oh La La inside with the almanac contents. (01:21:00 - 01:40:00)
Correction: That was actually the dust cover from the almanac that Marty tore off; Biff hid the copy of "Oh La La" inside the dust cover while keeping the almanac hidden inside his jacket. BTTF2 Marty took the almanac back shortly after Biff was knocked out by George; the almanac minus its dust cover was what Biff stole back from Marty.
Corrected entry: Doc and Marty could not know where the 2015 Marty lives and go there to get 1985 Jenifer.
Correction: He'd been there once before taking Marty to the future. When hearing about Marty McFly. Jr, he could have done a background search on him, including age, phone number, and address.
Corrected entry: In 2015 when the police get 1985 Jennifer to her home it's daylight, and they say "it's gonna be night time when we get there" but if they are flying that trip should be only a few minutes.
Correction: Doc, Marty, and Jennifer arrived in 2015 at 4:29 PM, already later in the afternoon. Doc also mentions that the skyway was jammed, meaning it would take flying cars longer than normal to arrive at their destinations. It's perfectly plausible that it could be dusk/dark by the time the police get 1985 Jennifer to her "future" home.
Corrected entry: After Marty burns the sports almanac, it is only burning for a few moments before it begins to pour rain. There was not enough time to burn the whole book, considering he started the fire with some cheap matches and no gas or lighter fluid to make it burn faster. Some of the pages may have survived. There would have been water damage from the rain on the remaining pages for sure, but a few pages may have still survived and have been legible enough for a passerby (or maybe even the western union guy) to be able to read and use to make bets.
Corrected entry: When the "old Biff" steals the time machine in 2015, as Doc and Marty attempt to retrieve Jennifer, it shouldn't be possible for Biff to return to the world that exists around him, as he gets out of the car back in 2015. Doc, Marty, Jennifer, and the world around them ALL should no longer exist, while still trying to escape from 2015. An alternate time line should have been created the moment "old Biff" left 1955. (Thus, Doc's explanation to Marty via the chalkboard explaining an "Alternate Reality"). This all started in 1985, and one result of old Biff's ventures, we learn that Doc is committed to an institution and couldn't even invent, or at least complete, the time machine by October 26th, 1985, which is the starting date of the initial film.
Correction: It is pointed out in all 3 films that the time lines aren't altered immediately (e.g. In the first film, Marty and his siblings fade out of the photograph that he holds, rather than just simply disappear). Just because Doc didn't invent the time machine doesn't mean someone else didn't instead (it is possible Marty did it himself using Doc's notes).
Correction: The official comics reveal that Doc had been performing time travel experiments in order to correct the timeline (this is the reason he was committed in the first place). These experiments didn't use a DeLorean, but still nonetheless involved time travel. In addition, an explanation of temporary "protective bubbles" that weaken as chances of timeline correction fade is also present.
Corrected entry: When Old Biff hands Young Biff the Almanac, the book passes through the film split (the vertical bar that divides the windshield) perfectly because it was on a motorized rig. But the stand-in for Old Biff didn't hold his arm at the right height, so Old Biff's arm disappears into the bar that runs down the middle of the window while the book floats across to Young Biff.
Corrected entry: In the scene where Doc lands the DeLorean in pouring rain in 2015, after a while the rain stops, and it is sunny and you can see the clock tower is in full light when Marty looks at the newspaper. But when Marty, after putting on his new clothes, walks on the street, it is cloudy again.
Corrected entry: When Marty and Doc successfully save Marty's son from going to prison in 2015, the USA Today headline spontaneously changes while Marty holds it. If this is possible, then, when Biff steals the DeLorean to deliver the almanac to his younger self, Marty and Doc's memories would be instantly replaced by those of the alternate 1985 - which would mean that Marty would not be baffled by bars on his windows or locks on his gate when he arrives back home there. In fact, they wouldn't have returned to that house at all.
Correction: Throughout the course of the three films physical objects change but Doc and Marty retain the bulk of their memories from alternate time lines, apparently protected from time line changes. Since it's all science fiction we'll have to assume it works the way it is shown in the film.
I would add that there seems to be a proportional relation between the historical event being altered and when the change takes root. Thirty years between alteration and changed result seems to take nearly a week. The event of the arrest and trial is only a day (two at most) in the future. Thus, presto-changeo.
The newspaper regarding George McFly changes after less than a minute as well, and that paper was published in 1973, so some doubt about the proportionality idea there.
Corrected entry: How did 2015 Biff know how to operate the time machine well enough to get himself back to see 1955 Biff? He learns about the existence of the time machine from an overheard conversation, which does not include any details of how to set the time circuits nor the requirement to accelerate the car to 88 mph in order to start the time jump.
Correction: This is a question, not a mistake. Given that the time circuits are not that complicated (it's a keypad with a display clearly marked DESTINATION) and that Biff also saw the time machine in use in 1985, it might not have taken him very long to figure out: 1. Punch in numbers and 2. Go fast. Not that he needed a short amount of time to figure out. This is a time machine, after all. He could have stolen the Delorean and then spent weeks figuring it out, with Doc and Marty none the wiser as long as he returned it to a time moments after he stole it. Not to mention that Doc may have left materials (like the videotape of the Delorean's test run from the first film) in the car that could have facilitated Biff's figuring it out.
Corrected entry: After Marty gets a crack shot on wild gunman, the screen is black. But when you see the arcade machine, just before Marty Jr. says, "Griff, guys, hey," you see the screen is on.
Correction: There are twenty seconds between the two shots in question. The 30+-year-old machine could simply have been resetting itself after Marty had scored his "crack shot."
Corrected entry: Doc puts Jennifer to sleep because she was asking too many questions about her future, and according to him, no-one should know too much about their future. But when they have landed in 2015, Doc doesn't see anything wrong with telling Marty, at length, what is going to happen to Marty in his future.
Correction: Character decision, not a movie mistake. Marty is already completely informed about the time machine. Doc is taking a calculated risk that the 1985 Marty can fix this one event (that ruins his kid's lives) without severely disrupting the existing time line (from 1985 to 2015). Doc does not disclose any information to Marty about his future, only about the future of Marty's kids. Putting Jennifer to sleep with the hopes of making her think it was all a dream would ensure that she does nothing to disrupt the time line.
Corrected entry: In Back to the Future 1 after Marty goes to 1955, you see a sign that says "Hill Valley 2 Miles". Later in the movie, Marty talks to George and Lorraine then walks out the door. The next scene you see Marty with Doc in his 1985 explaining that he needed to change his clothes, and than there is the whole sequence where Marty goes back to 1985. In 1955, in Back to the Future 2, Marty is standing outside the gym when Biff approaches him. Marty is knocked down by his earlier self, and Biff steals the Almanac. Then Marty steals the Almanac, burns it, sees Doc get struck by lightning, receives the telaeraph, runs 2 miles back to Hill Valley, just to meet Doc after his previous self goes back to 1985. How is it possible for on Marty to do the thing previously stated, while the other one dresses and drives to the Clock Tower, taking up the same amount of time?
Corrected entry: When 1985 Marty first puts on the "future jacket," the sleeves are really long (can't see his hands or anything), but after Doc comes up (and before he pushes the button to make it fit) you can see Marty's fingertips, and the jacket only goes up a short bit.
Correction: Marty is holding the sleeves up. That's why you see his fingers.
Correction: There's a split second shot of the Pitbull leaving Griff's feet and flying away. The direction it went and how far isn't shown. It could easily have gone where the little girl could pick it up.
Grumpy Scot
True. There is a shot of it leaving Griff's feet and landing near the steps of the Courthouse Mall. It's hard to see but I'd say pausing or slo-mo isn't needed.