At the very end of the game, three different future versions of Marty show up, all asking for him and Doc's help. But shouldn't at least two of them be in the process of fading away if their timeline isn't currently dominant?
Presumably, the ripple effect had not caught up with them yet.
The comic book Astro City addressed this phenomenon perfectly! In a story three future versions of a character showed up. All three of them existed because in rodenberrian physics terms the quantum states for the existence of each was equally probable at that moment in time. As the adventure progressed and events unfolded one faded away then another leaving the final, 'inevitable' future version.
When Marty returns to 1985 at the end of BTTF and finds out that his entire family is different... where the hell is 1985' Marty? BTTF2 and the Telltale games establish that each version of 1985 has a Marty that is doing stuff (run out of town, run out of town again, camping, what have you), but won't they eventually return? And if they somehow vanish when original!Marty appears, he isn't getting the new memories of those timelines, so even when he finally gets back to 1985, his life could potentially be very different, and he wouldn't know what he should. - Alphacat
At the end of BTTF, Marty returns to see the "new" Marty leave in the time machine as Doc is shot at by the Libyans. Where that Marty went at that point is subject to Wild Mass Guessing.
Possible Fridge Horror: That Marty went back to the same week, but was a Marty of an alternate timeline, henceforth events played out differently and (assuming this new Marty made it back at all) he too would be coming back to an entirely alternate timeline from Marty-A.
This one is simple: The 1985's Marty you ask for, just went to 1955, and lived through everything the other Marty did. It's a Stable Time Loop of Marty giving confidence to George, and George raising Marty as a determined man. The Marty who we see in Back to the Future Part I is the one who started the Loop.
Adding to that, when time must catch up to itself, it establishes changes based on the current timeline. When Marty returned he saw that he still existed, meaning it would only be a matter of time before Marty would completely forget about his old familial life and instead be replaced with the memories of his current one. The way this works is similar to the slow fade-out of Marty's hand, except where that was erasing him from existence in this case it's simply reassembling Marty's identity, which is EXACTLY why in the following films his personality changes to reflect his new upbringing (i.e. his need to defend his honor when someone calls him chicken because he now grew up with a confident, assertive father figure).
Shown when Jennifer shows up in BTTF Part II. Yes, she was played by another actress, but she could have had different DNA but marty would only recognizer her as Jennifer, not "why do you look different" Jennifer.
What the "new" Marty that the "original" Marty inadvertently created would experience when going back to 1955 does raise some questions. It can't be exactly like the "original" Marty's experience. Presumably he would push young George out of the way of the car, preventing his parents from falling in love, just as original Marty did. But he wouldn't think he was changing the way his parents met, because he grew up in the altered timeline where George never got hit by the car. It raises the question of what the George and Lorraine of the altered timeline told their kids regarding how they fell in love. Did they mention that Lorraine briefly fell for a mysterious young man who seemed to come out of nowhere and then never was heard from again, before George succeeded in winning her heart? If so, this Marty might put two and two together and realize he was the young man they spoke about—in which case his experience would look a lot like the "You Already Changed The Past" trope. And that would affect the whole way he and Doc come to view time travel, because it would make the past seem much less malleable to them. In that case, you wonder why he or Doc would even bother to try to meddle with time like they do in the sequels, creating even further paradoxes... Ok, I have to stop, my head's starting to hurt.
In BTTF 3, Marty suggests to Doc that they bring Clara to 1985 with them, but Doc dismisses this, mentioning that it's not worth disrupting the timeline. However, in the original timeline, Clara fell into Shonash Ravine and died anyway, so bringing her with them would actually preserve the timeline.
Except, now it's "Eastwood Ravine" instead of "Clayton Ravine."
Consider the events of Part 2 from 1955 Biff's perspective. A crazy old man gives him a book containing information about the future. Later, he has the book stolen by 'Calvin' after being beaten up. Biff catches up with him and retrieves it. 'Calvin' inexplicably shows up outside Biff's moving car, gets the book back and is saved from being run over thanks to a flying car. Biff then crashes into a manure truck for the second time. Biff's not going to forget about all this. You'd think he'd figure out in the 1980s that Marty McFly really, really looks like the guy that ruined everything in 1955.
Even if he does put two and two together and doesn't just chalk it up to a coincidence, what's Biff gonna do? Marty's father is the same guy who punched his lights out all those years ago when he tried to rape the woman who is now Marty's mother. Chances are, George isn't going to react any better towards Biff trying any funny stuff with one of his kids, and this Biff doesn't own the cops in this timeline. Even if he does figure it out, Biff has little choice but to suck it up.
Perhaps Biff, and a number of others who knew 'Calvin', think that Marty is the result of Lorraine Cheating with the Milkman. The fact that 'Calvin' vanished means nothing - they'll just assume he moved and kept in touch with Lorraine.
This is why Biff is such a cowed bastard around the Mc Fly's. Because of all of this he is really, really scared of them. At the same time he probably has chalked all his weird memories about the book and everything up to just being a nervous breakdown, which probably precipitated a real nervous breakdown.
Since Marty's ancestor Maggie Mcfly looks like his mom Lorraine Baines, does that mean the Mcflys and Baines' are related somehow?
No. Word of God is that Mcfly men are just predisposed to find people who look like Lorraine attractive.
The whole first movie is basically about Marty having to navigate around the Oedipus complex; this should not come as a huge surprise.
In Part II, when Marty and Doc get back into the DeLorean after Biff used it, why didn't they notice that the time circuit readout had changed? There's a readout for telling the time traveler when the time machine had been last, and after Biff used it, that would have read "November 12, 1955" when before it had read "October 26, 1985." And considering from there they got back on the skyway, they had plenty of time to notice before they jumped back to 1985.
Later on in the film, the readout is shown malfunctioning. Doc may have thought this was the first time the time circuits glitched out, or the time circuits had already been malfunctioning, and was showing a readout of 1955 for whatever reason.
The time train. I'll accept the Hand Wave that it runs on steam, fine. But how the hell did Doc convince a mechanic in 2015 to hover-convert it? How did he even get it to them in the first place? After all, it's a train. They're generally not known for doing all that well when off their tracks.
He couldn't have had a 2015 mechanic do it at all (because there'd be no more way to get the train up to 88 mph without running the same Future-Or-Bust risk that he and Marty take in III). He had to have done it himself.
Fridge Brilliance: He had saved the unused damaged flying parts from the DeLorean and simply waited until available resources were discovered to either repair them or re-engineer their mechanics. This is why when we see the Doc again, enough time has elapsed for him to have two young sons.
On the other hand, as of September 1, the Doc had given up on repairing the De Lorean or, presumably, building another time machine. He had also decided that the De Lorean must be destroyed because it could only cause heartbreak and disaster. When the train appears, it's clear that all that has changed. Why? In a word, Clara. She's shown to be extremely intelligent in her own right and may have suggested 19th-century solutions to some of the problems with making a working time machine, and she has probably changed the Doc's outlook on life to be much more optimistic.
How long can the necessary power from a bolt of lightning persist in a power line? Doc and Marty know the minute the lightning bolt struck because of the flyer but a lightning bolt travels really fast and Marty has to hit the power line driving at 88 miles per hour with at the instantaneous moment that the line is being flooded with electrical current. It would seem to me that know the minute of the lightning bolt strike is not nearly good enough.
The only way I can think of to get around this is to temporarily store the power in an array of ultra capacitors to be discharged on contact with the wire, and after all Doc is an expert in capacitors since he built an entirely new kind of capacitor that somehow enables time travel.
Actually, this works without anything exotic. The amount of energy stored in a capacitor is ˝CV^2 where C is the charge and V is the voltage. in other words, quadruple the charge and you just quadruple the power, quadrupe the voltage and you increase the energy sixteen-fold. Lightening is extremely high voltage so not very much capacitance is needed. the parasitic capacitance between the wire and the ground may be enough even. In any case, very high voltage capacitors were some of the first electrical components created and would be easily built by someone familier with electronics with 1955 or even 1855 materials.
Doc Brown made the deal with the Libyans to obtain plutonium in 1985. That means he made the deal specifically with Muammar Gaddafi.
Or the Libyans behind the Pan-Am Flight 103 originally planned to detonate a nuke aboard a plane and Doc cheating them set their timetable back 3 years.
Based on what we know from the sequels, Doc's reassurance to Marty at the end of the first film that "you and Jennifer turn out fine" isn't quite accurate. Of course, the filmmakers have explained in interviews that they had no plans for sequels when they made the first film, and that they intended this scene merely as an amusing throwaway. So apparently they ended up developing the story of Marty and Jennifer's future a little differently than the first film suggested. But compare the way Doc delivers that line in the first film with the way he delivers it in the reenactment of that scene in the second film. The difference is subtle, but real. In the first film, he speaks the line matter-of-factly, and he has a sincere expression on his face. In the second film, after hearing Marty's query "Do we become assholes or something?", he pauses, his eyes turn to the back of his head for the briefest of moments, then he sputters, "Oh no no no no, you and Jennifer turn out fine." Unlike in the first film, it looks like he's hiding something. Considering that we later find out the pivotal accident which ruins Marty's musical aspirations is set to occur later the same day, and Doc knows it, that shouldn't be surprising.
People often complain that Marty didn't conquer his fears or do what his dad did and get extra confidence to get his dream career. I thought the same until I thought of it, Marty was terrified that people were going to reject his music, and only did the audition in front of a few teachers, but he got over it and managed to do it in front of hundreds of people. Sure they didn't like the end of it, but he is so confident by the end of "Johnny B. Goode" that he says "I guess you guys aren't ready for that yet. But your kids are gonna love it!" He might not just be talking about Rock & Roll but about his music as well.
In Part 3, when waiting for Doc to fire the "starter-pistol" to let Marty know when to floor it for the screen of the drive-in movie theater, you hear Marty quip, "Hi-ho, Silver." What color is a DeLorean?
When Marty first shows up at 1955 Doc Brown's house in the first installment, he's testing a thought reading device. He makes a series of guesses as to why Marty is there, ending with noticing Marty's jacket and asking if he's looking for donations for the coast guard. Running gag, OR, did Doc actually pick up the memory of Marty being asked if he's with the Coast Guard earlier in the day?
He sure did. "You come from a great distance?" refers to how Marty traveled 30 years from 1985 to 1955. Next, "You want me to buy a subscription to the Saturday Evening Post?" refers to how Marty uses a newspaper to verify that he's in the past. Lastly, "You want me to make a donation to the Coast Guard Youth Auxiliary?" refers to both the woman who wanted donations to save the clock tower in 1985, and the fact that a few people in 1955 (Lou the cafe owner, Skinhead the gang member, and Stella Baines) thought Marty was a sailor judging from his vest.
On the other hand, Doc is touching Marty's vest before he says the stuff about the Coast Guard, so he clearly isn't getting this one from his machine. Later, he himself says that the Time Machine is his first invention that actually worked.
While several characters from the '50s naturally assume Marty's vest is a life preserver, it is Marty who tells Lorraine's mom that he works for the Coast Guard. Doc doesn't know Marty said that, yet he's the only other person that day who associates Marty's jacket specifically with "Coast Guard." That seems a funny coincidence, and does lend support to the idea that the mind-reading device really is picking up something.
I just figured that Doc was too distracted by the apparent failure to notice that he had achieved a partial success.
To be fair, after Marty explained what happened, Doc says that the thought-reading device "doesn't work at all!" Maybe Doc considered it one of his few working inventions in Twin Pines' 1985!
Plus, Marty's probably not in the best state of mind anyways, so his head's gotta be all over the place even before Doc suddenly hooked him up to the crazy hat without explanation.
Why does the DeLorean lack a rear-view mirror? Not only because vision the back is blocked off by the time machine engine, but to avoid reflecting the light of the flux capacitor into the eyes of the driver. (There's a label on the glass which warns of blinding light.)
It's also a neat metaphor. When you're in the De Lorean, you don't need to look back, because you can always go back.
If the Libyans knew jack squat about building a nuke, they never would have gone to Doc Brown in the first place.
Doc Brown burned down his house, wasted his family fortune, and spent 30 years trying to invent his time machine. In 1985, he is reduced to living in his former garage next to a Burger King, driving a shady truck advertising "24 HR Scientific Services," and hanging out with ignored and insecure high school kids, all the while being treated as an outcast by his community (even Strickland calls him a "real nutcase"). It's plausible that Doc has cultivated black market connections in order to make some money and get the raw materials he needs for his experiments and inventions. These connections probably helped him get in touch with the Libyans and even corrupt officials at the nuclear research center in order to get the plutonium he needed for the time machine.
Also in the first film, regarding Marty only setting a few minutes' worth of lead time in returning to the past: keeping in mind that Marty didn't want to screw up the timeline worse than it already was (he knew he couldn't run into himself in the future/present), he gave himself as little time as possible to screw things up in. Also, he wasn't expecting the DeLorean to fail on him.
Alternatively, Marty simply has "no concept of time". Marty could have wasted his only opportunity to go back to the future because he felt he needed to change his clothes. Moreover, at the beginning of the film, he arrives late to school for the fourth day in a row. Granted, the Doc set his clocks back 25 minutes on the fourth day, but why was Marty late the other three days? Maybe he's just a habitually late person. The reason he only gave himself ten minutes to warn the Doc was because Marty completely underestimated the amount of time required to tell him, with or without the car.
Another in the first film: Doc says he's calculated the exact time Marty has to start to hit the cable the instant the lightening hits. Marty misses the start time, but still gets there in time. Why was Doc wrong? He miscalculated the DeLorean's more advanced acceleration compared to the contemporary cars he was familiar with.
Worth noting the DeLorean hits 88 miles an hour well before it hits the cable.
Marty's plan was really kind of dumb. Even if he had arrived in time to warn Doc, his very appearance would have probably screwed up time again, because it would have prevented 1985 Marty from being sent back—thus generating a new paradox. Marty wasn't thinking clearly when he came up with the "10 minutes early" plan, because he was desperate to save Doc's life, and he was already a reckless and impulsive teen who still didn't fully understand the consequences of meddling with time.
In Part II, why did Biff never get suspicious about the flying DeLorean he saw in 1985? Because at some point after that, flying cars become widespread, so he must have assumed it was a prototype.
Also, the car accident that messed up Marty's life happens as a direct consequence of him fixing his family in the first movie, because in the unchanged timeline Biff wrecked the car, so Marty couldn't have drag raced anyone. The sudden appearance of Marty's chicken problem may also be directly linked to him now trying to live up to the high standard set by his overachiever father, instead of struggling with the poor self-confidence learned from his unaltered father.
I agree with the theory about him not really being suspicious about the flying DeLorean. He even acknowledges that memory in 2015: "A flying DeLorean! I haven't seen one of those in... 30 years..."
I always assumed that he WAS suspicious, but had no idea what could possibly have caused it. Eventually just filed it away in his mind as a memory that had occurred AFTER flying cars became common.
In the second and third movies, Marty suddenly seems to have a problem with being called "chicken" (or "yellow", etc.) Although it seems to come out of nowhere, but in the first film no one calls him chicken, they may call him a lot of things but no one really questions his bravery.
It may also be that after the events of the first movie, Marty's father now has a reputation for bravery and standing up to bullies, that Marty may feel now obligated to live up to.
The whole "chicken thing" may actually be from the original timeline. Remember Marty originally never liked being compared to his father becuase he thought of his old man as a coward. Even after the timeline was changed, that habit still lingered.
He had 5 minutes with his new dad before Doc picked him up. My guess is that it's the ripple effect. In the ideal 1985, Marty has grown up with his cool dad and has become a bit cocky about it, and his new traits are slowly replacing his old ones of original 1985.
In the Telltale game, Marty makes a reference to the Mario brothers. This gets really interesting when you consider that Super Mario Bros., the game most people know Mario from, came out in North America in March of 1986 - about two months before the game starts. It's likely it was on Marty's mind because it had just come out and he was currently obsessed with it (much like how Wild Gunman would have come out less than two months before the time Marty came from in the movies).
Alternately, Marty could've been referring to the earlier Mario Bros. game, which was released in North America in 1983.
Regarding the Ripple-Effect-Proof Memory in the first movie; Marty's actions in 1955 caused his brother and sister to be completely erased, then remade, in time. However, he himself was only partly erased before being brought back. This would explain why he kept his old memories, whilst still having some personality changes (e.g.; the "chicken" problem, deciding to send his demo tape into the record company after all), even though the rest of his family are now completely different.
The end of Part II. Seems to be a bit of silly movie magic that the mailman arrives exactly on time, doesn't it? But this is a letter that they'd been holding for a century, a package that would have been increasingly the topic of conversation as the time drew nearer. They had a betting pool going as to whether or not this "Marty McFly" was even going to be there. They likely had some debate over who would actually deliver it. If you had the opportunity to confirm or debunk a one hundred year old urban legend (even if it's only an urban legend around the office), wouldn't you take an almost extreme amount of precautions to ensure that you got there when you were supposed to?
But why is he alone?
It's late at night when he delivers the letter, chances are he's the dumb schmuck who got stuck having to stay an extra four or five hours to do the job while everybody else who works there went home. After all, their manager is probably a sensible enough man to know that sending a mob of Western Union reps to make a single delivery could be pretty intimidating (and bad for business!) and he wouldn't want to have to pay them ALL overtime. Either that, or Doc just told them not to go out of their collective way when the time came.
Or maybe he was the only one who didn't bet in the pool, so is the only one who could be trusted (how easy would it be to either "forget" to show up and say there was no one or throw the letter into the bushes and say "Yeah, I gave it to him!"
Except, if I recall correctly, he said that he lost the bet.
Maybe they drew straws within the betting pool, and he just happened to be the poor shmuck who drew the short one.
I think simple curiosity would do the job to encourage him or whoever got nominated to play fair and do the job. I mean, yeah, you could hang around in a bar for a few hours and say he never showed up or throw the letter into the bushes and easily win the bet that way, but ... wouldn't you spend the rest of your life wondering? Wouldn't it niggle at the back of your head for all those years and eat away at you, that you had one chance to settle this little mystery once and for all and you pissed it away? Why not follow the rules and show up, just to settle it one way or another?
It's also his job to deliver letters like that. They probably had a sense of pride fulfilling their duties.
The Telltale game again, episode 2 this time. If you examine the bug zapper in 1986 before Biff and his brothers show up, Marty wonders when they got it, implying that it wasn't there in the alpha timeline and came about as a result of the alteration. Considering the only net major change made to the timeline was Kid Tannen's non-arrest and the resulting skyrocketing of crime in Hill Valley, you'd think doing something about the bugs on the front porch would be the farthest thing from the McFlys' minds. So what's the connection? When I saw Marty exploit its presence to KO the Tannen gang, a theory came to mind: the bug zapper was deliberately put there as a Tannen trap. The "past" Marty, being the clever little punk he is, had it hung there and perhaps upped its voltage for the primary purpose of using it to shock the Tannens into giving up the fight whenever they came to collect, much like the "present" Marty did. Small wonder the Tannens had to run the "past" Marty out of town...
It seems it's time I defended my logic. The bug zapper's still there in Episode 3, even though Hill Valley's now run by Citizen Brown instead of the Tannens. It's simply there for the proper purpose of a bug zapper in this particular timeline (if dust mites are sufficient to get a whole house quarantined, of course they'll take the bugs on the front porch seriously). In fact, maybe the bug zapper's preservation is an example of how time likes to keep its alterations minimized whenever possible. "The universe eats paradoxes for breakfast" sort of deal. I don't know how to explain it better.
Another one for the Telltale game, this time for Episode 3. When Marty was finally convincing Citizen Brown that they could fix the DeLorean, Marty shows him Doc's notebook, which naturally should be blank as Citizen Brown never invented a time machine. The notebook is indeed blank except for the drawing of the Flux Capacitor. Why would the drawing of the Flux Capacitor not be blank as well? When Citizen Brown looked closely at the drawing and then looked closely at his own logo, he has a moment of dawning comprehension and is then completely convinced that he could fix the time machine. A good eye would notice that Citizen Brown's logo actually DOES look vaguely like the drawing of the Flux Capacitor. The drawing of the Flux Capacitor still exists because Citizen Brown had the exact same accident that Doc did and based his own logo on his vision of the Flux Capacitor!
It's made clear that Hill Valley is kinda crummy and pretty inconsequential. But Marty and Doc are very lucky that this is the case, because it makes it the perfect testbed for time travel. No matter how much they alter Hill Valley's history, it won't greatly affect the rest of the world, which makes messing up history less catastrophic, and makes it safer to alter history for the better (e.g. Marty's family, Marty's kids and Clara Clayton). This is explicitly stated in the Telltale game, in which changes that could potentially affect the world fail to to do so miserably; in Episode 2, the prevention of Biff's gangster father's imprisonment results in the existence of the fifth biggest crime syndicate in the state, and in Episode 3, the alternate Hill Valley's strict societal model only has one other adopter, the already law-heavy Singapore.
This wasn't always the case, however. In Btt F 2, Biff's meddling with the timeline somehow got Richard Nixon elected to at least four terms and the Vietnam War is still going on as of 1985.
The Telltale game episode 3. "X11" is the code you have to set a Citizen Plus' watch to in order to induce a hypnotic trance. X11 seems like kind of a random letter-number combination, doesn't it? Not exactly. It's not X11, it's XII— the Roman numeral for twelve. This is in perfect keeping with the clock motifs that tend to haunt Time Travel stories.
The ending. Marty and Doc are naturally confused by the fact that Edna and Kid were married and well-adjusted... except when one remembers that Citizen Brown didn't want Edna to become a Crazy Cat Lady in 1986. Because of Citizen Brown's interference of Marty, he guaranteed that Edna would have a good future!
In Back to the Future Part II, after Biff returns the time machine, he seems to be in pain or dying, getting out of the DeLorean. I could never understand this. Was he having a heart attack? Did he hurt himself with his cane after getting it stuck and breaking it? And what was the point in even including that scene? But in rare example of a deleted scene actually being worth watching, one on the DVD reveals all. He has interfered with his own past and destroyed his own existence! He gets "erased from existence". Just like Marty nearly did in the first part! And just like the Doc is always warning about! The only question I have now is why they took that scene out... they said that test audiences didn't understand it, but surely that explains what is otherwise a very puzzling scene, and adds a touch of brilliance to the movie.
It's probably because it highlights one of the plot holes: if Biff "erased" himself by going back in time, then surely the same thing should happen to Doc and Marty. Or they should be replaced by new versions of themselves. Or Marty should have disappeared just as fast in the first movie. Etc. I think cutting the scene was a good idea - it challenges your suspension of disbelief.
But there's the brilliance: in either of the timelines from the first movies, Biff doesn't have sufficient funds or opportunities to afford all his vices. Hence he probably doesn't have the money to do, say, very hard drugs or alcohol for decades on end. But once he has the almanac, he does. The problem being that, given he can now afford all his vices, the odds are good he's going to die of a drug overdose, or heart attack, or whatever — he's not going to make it to the old age when he would have originally seized the almanac. Hence he does a quick fade-out and dies when he returns to the future — by giving himself the almanac, he's taken several decades off his own life.
Actually, if Biff was to adhere to the same rules as Marty and Doc, he probably could've lived on, but wouldn't have jumped back to the same timeline where Marty and Doc are (at Marty's future house). He'd have jumped back along the new timeline where he's a rich asshole. Marty and Doc would've been stranded in 2015. Of course, much of the time mechanics they use don't make sense anyway.
The reason why they decided to cut that scene is simple: had Biff disappeared, so would have the piece of his cane he dropped in the time machine! The scene where Doc finds it and shows it to Marty would have made no sense.
A theory that's been thrown around the internet, which is borne out in the Telltale game, is that 2015 would have changed into 2015-A around them, but this particular time they didn't notice because they were busy carrying Jennifer down the street. In the Telltale game, time is rewritten around the time travelers when Edna destroys Hill Valley in 1876, causing the town in 1931 to be replaced with empty land. Hard to overlook something like that. As for why time travelers don't get overwritten when the time they're in is? Ripple-proof handwaving, I guess.
Wordof God suggested that Biff of the alternate 1985 ended up pushing Lorraine a little too far, and she shot him dead some time in the 90s, hence his disappearance when he returns to 2015. The test audiences could hardly be expected to guess this without further clarification, and without it the situation was too ambiguous, so they removed the scene.
Going back to the fact that Biff was erased much quicker than Marty, there's actually a simple answer to this too. The only reason Biff was erased so fast is because he went into the future past the point of no return. Marty still had time to save himself in 1955. If Marty had gone straight to 1985 without fixing his parents, he'd be gone in a blink just like Biff. My point being, Biff probably would've survived for the duration necessary to save himself, but instead opted to jump ahead giving himself no time and resulting in his immediate death.
Also from Back to the Future Part II: How is 2015 Biff able to use the DeLorean Time Machine the way he does? Simple: He's a bit of a gear-head. In 1955, his '46 Model Ford has a special trick to starting it; a trick that only Biff knows. After Marty's changes to 1985, Biff has an auto detailing business set up - a business he still dabbles in by the year 2015. By then, I'm sure he's worked on a few cars with hover conversions. Combine that with the memories of seeing the flying DeLorean in 1985 and his eavesdropping on Doc and Marty's conversation in the alley, then you get how he's able to operate (to the best of his abilities [he is old, you know]) the time machine.
Also, here's the logic to why Biff disappears fast and Marty didn't. Marty was fading out of existence slowly mainly because he was still before the point in time that would've ensured his birth. If Marty didn't get his parents back together by that moment and just left for home he would've been erased just as fast as Biff was because like Biff he wouldn't have logically existed in the time he was in and time would've caught up with him. Take this into account, when Biff is in the past giving himself the almanac he's perfectly fine. This is because Biff (like Marty) is preceding his point of non-existence and therefore technically still had time to correct the mistake which would lead him to inevitable death. Honestly, it's surprising test audiences didn't get it cause it'd be pretty easy to figure out without anything having to be explained that what he did in the past erased his own personal future. Also, since the cane top and the bag had been left away from Biff's person they didn't fade with him, kinda like how the guitar didn't disappear with Marty. I hope that clears up a couple of things.
The cane also wouldn't have disappeared because it would have been manufactured despite Biff, not because of him; Biff might not have been around to buy that particular cane, but someone somewhere would still have made it. (Of course, this opens up the further plot-hole that someone else would have purchased it and used it.)
Here's an example from Back to the Future I never thought of until I saw it for the umpteenth time: Marty's father's explanation for why he was in the street to get run over by Lorraine's father? Birdwatching. Well, he was packing binoculars, but that's not the only reason it's appropriate. He was there looking at Lorraine. What's 50's slang for an attractive young woman? A bird. He was, so to speak, literally bird watching.
From BTTF 2, I always though that the police woman telling Jennifer to "be careful in the future" was a very strange, generic way of referring to the time they occupied as The Future. Only after about 15 viewings did I realize that Jennifer was still suffering from the wooziness of Doc's knockout gas, and (correctly - she is in her personal future) misinterpreted what the officer said. What would have been less awkward was "Be more careful in the future", i.e., don't let that happen again.
This one's really minor, but I didn't notice until I watched BTTF 2 for the Nth time that when A-Biff shows the Almanac it wears a plastic cover. The reason is obvious: Biff lost the original paper cover in 1955 when Strickland took the Oh-la-la magazine from him.
In the same scene, why does it take so long for Biff to follow Marty when his Mooks come out of the elevator? His gun holds 5 bullets, all of which he uses before Marty exits the lounge. He had to go back for more bullets!
Lastly, why did Marty go to the roof? Having Doc show up on the side of the building was the plan all along. Notice how Marty looks down and swears.
As a longtime fan of the series, I always found it odd that the third movie would begin with a slow panning of Marty, just, sleeping. It wasn't until just now when I realized why - the poor guy spent the entire previous movie running around solving problem after problem, with no breaks in between (unless you count getting knocked unconscious). With all that in mind, it's very satisfying to see him gets the rest he so very deserved!
Not to mention that, if you do the math, he'd been awake for over 24 hours straight (excluding the "almost 2 hours" of the KO), with a significant amount of tiring physical activity, much of which takes place in the last three of those hours.
If you extend this further, Marty has had a hell of a couple of weeks. Week or so in the past, get back, go to sleep, wake up, see the new 1985, go to the future, go to bad!1985, go BACK to 1955, run around, go to the wild west for a week, and then back to 1985 again. Marty just can't catch a break. - Alphacat
Also, Marty and Jennifer don't get their weekend down at the lake. Both have spent the whole weekend time traveling and/or passed out.
This comes up in the games series as well. Episode 5 starts with Marty hardcore passed out (he still has his shoes on). When he asks why no one woke him, he's told that he looked like he really needed the rest, and asked how long it's been since he slept. He has no idea: between all the time-travel shenanigans, he has no concept of his personal time.
The first movie makes mention of Marty's uncle Joey who is perpetually in prison for one reason or another. Once he goes back to 1955 he sees his uncle as a baby who is always sitting in his crib and his mother (Marty's grandmother) says that he just cries whenever they take him out so they just leave him in there and move the crib around the house. It wasn't until years later that I realized Joey feels insecure without the bars and most likely suffers from some mild form of mental illness and thus commits crimes to get into prison and thus feel "safe". In the altered timeline, George has enough money to get him the help he needs.
Why does Old Biff choose to go to November 12, 1955 to give his younger self the almanac? Because he remembered betting on a game that had a sudden reversal for an unexpected outcome on that date, and that would hopefully prove to his dim-witted younger self that the almanac was real.
Also, he likely considers it the defining day in his life, when George made him a laughingstock. It makes sense he would pick that day to "fix" things.
After seeing Part II again just now, I laughed when Doc Brown says "If only the postal service was as reliable as the weather service", because at the end of the movie, the postal service shows up at the exact spot at the exact second stated in the letter from Wild West era Doc to Marty.
That was Western Union that held the letter, not the USPS.
It's better than that, in 2015 Doc knew exactly when the rain would stop thanks to the excellent weather service. 1955 Doc was worried about his 'weather experiment' because "the weatherman says there isn't going to be any rain". So 1955 has bad weather forecasting but excellent mail delivery while 2015 has perfect weather forecasting and unreliable deliveries.
So in the first movie, Lorraine falls in love and later marries George after he is involved in a car accident because she feels sorry for him. In the second movie, it is implied that Jennifer marries Marty because she feels sorry for him after he is involved in a car accident. Can't believe it took me so long to realize that.
So he avoids an unhappy marriage that started on a weak foundation. Hardly that horrifying. Maybe he and Jennifer get married for better reasons?
Heck, even avoiding a stellar marriage seems uneventful, for some that have witnessed love coming and going like the breeze.
Working this out in a vacuum... (shut up; some of us who didn't grow up with the internet don't realize that pre-internet subjects are scrutinized by anyone on the internet.) I always assumed that Doc was just crazy and had set all of his clocks wrong, not that his house being non-synchronous was an earlier experiment... until the umpteenth rerun.
And I've assumed that Marty had always been vulnerable to coward-adjectives: complete immunity to ripple effect still inconclusive.
Okay, this troper has watched Back to the Future (the first one) for the 50th time and this plot point occurred to me. Why does Doc Brown continue to insist not letting Marty tell him about his death? And then it hit me. It wasn't just because he didn't want to know what's going on, but from the sequence he saw when he saw the Oh, Crap moment on the video he watched, he figured out that he would die. And because he knew of his death, he didn't want Marty to worry about his own death. At least this troper thinks so.
In Back to the Future III, Marty accepts a challenge from Buford, but plans on him and Doc being out of there before Buford arrives. However, knowing Buford, if he'd arrived in Hill Valley only to find that Marty had left town, I'm pretty sure all hell would've broken loose in one form or another, affecting 1985 in a bad way. Did Marty stop to consider this? My guess is probably not, but it sure is a damn good thing Doc can't hold his whisky.
In the third movie, Doc takes Marty to the desert to make sure that he has not an accident while he travels back in time, citing specifically that he could hit a tree that was there in 1885. What was the first thing Marty did when he time-traveled to 1955 for the first time? He hit a tree. Fortunately, only a small one.
Typically, a helicopter indicates to the audience that Marty is indeed back in 1985: we see one at the end of Part I (with the searchlight shining on the Clocktower) and we hear one at the end of Part III (when the DeLorean is drifting past the Eastwood Ravine sign). However, we don't hear one right away upon landing back in 1985 in Part II, helping the audience to believe that Marty may be stuck in the wrong year. However, we do hear a helicopter right at the moment when Marty gets the date from Strickland's newspaper, confirming that we ARE in 1985—just not the right one.
A double example: First, the paralleling color-themed names of the two mayors of Hill Valley in Part I, Red Thomas and Goldie Wilson. Secondly, could their last names be a reference (even unintentional) to Thomas F."Biff Tannen" Wilson?
Biff earns the nickname "Luckiest Man on Earth" in Part II after he uses the almanac given to him by his future self to get rich off of gambling. At first, you dismiss it because he's using the almanac to cheat. But think about it - how many of you have been aided by your future selves to get rich? In a way, he really is the luckiest man on Earth.
It was posed to me, why didn't Doc just give Marty a heads up that his kid was going to make a bad decision? Well because Doc had what he thought was a foolproof plan and didn't want to leave anything to chance. But then I wondered why Doc had to leap out of the car in future garb, shout to Marty that he needed to come with him right now (thus having to drag Jennifer along). Why not wait? Ask Marty to meet him at his house later and explain the situation in private? He's going to look like his son next week right? Well, no. Because Doc already knew about the accident Marty was destined to be in only days later and knew his time was short before Marty's injuries, changed mindset, and likely physical scarring would leave him unable or unwilling to risk another time travel adventure and impersonate his son.
I couldn't ever explain why Doc thought asking who the president of the United States was would be a foolproof plan to catching Marty in his lie; after all, how would Doc know if he was lying? But what his reaction to Marty's answer? "The actor?!" He thought that Marty, being just a kid, wouldn't be clever enough to think up a plausible name off the top of his head, and would resort to saying someone remotely famous. The joke becomes that much funnier now.
There's been a lot of speculation as to what happened to the Marty we see go back to 1955 at the end of the film (Marty II). I puzzled and puzzled until I stumbled across the scene in Pt. III in which Doc doesn't remember dressing Marty in those ridiculous clothes. Why is this relevant? This Doc, much like the Marty we follow throughout the films, is from a timeline which no longer exists, and has memories of it. This Doc does not recall his interactions with Marty set into motion by his own presence in 1885. However you explain it, somehow the mechanics of time-travel in this universe absorb versions of time-travelers with altered pasts into the original one without their memories (at least, as far as we can see) to maintain continuity.
One might wonder how the Sports Almanac would always have the correct sports results. After all, the worldwide proclamations of Biff's luck may affect the games in some way, such as which players join which teams, how players feel during the game, etc. Well, since the Almanac comes from the future, any changes to sporting results would be reflected in the Almanac by way of the Ripple Effect! 100% accuracy guaranteed!
With all the changes Marty made in the first movie, how could he and Doc Brown be sure that the time the lightning struck the clock tower hadn't changed too? By noticing that the "Save the Clock Tower" Flyer doesn't fade like the picture does!
Why were Doc and Marty falling out in Part III? In the original movie, Marty's father George had originally been a total wimp, so Marty looked up to Doc as a father figure. But in 1955, he bonds with young George, learning they were more alike than he'd originally believed, and it leaves a lasting impact, as in the new 1985, George is a confident, successful writer. George had become Marty's father figure once again.
Marty walks in on Biff while he's watching Clint Eastwood in the hottub. The scene in particular has Clint be shot several times and being knocked down, before revealing he was wearing a bulletproof vest. Sound familiar?
When 1955 Doc views the video of himself from 1985, he remarks, "Thank God I still got my hair!" It does seem strange that his hairline is at exactly the same level of recession in 1955 and 1985. (In contrast, Christopher Lloyd himself, 30 years after making the film, is almost entirely bald.) Maybe Doc invented something that halts, but doesn't reverse, hair loss.
A bit of a meta example - the first film was clearly designed to provide a nostalgic view of 1950s-era America and much Lampshade Hanging is done pointing out how much things have changed from the 50s to "present day". Except "present day" was in the mid-80s, meaning people reading this are now as far removed from the setting of Back to the Future's "present" as its original audience was from its "past" setting. Hilariously, the film is so jam-packed with 80s pop culture, from fashion to music to technology, the segments of the film set in "the present" are now just as much of a nostalgic throwback for children of the 80s as the past segments were for children of the 50s.
In the end of the Part I movie, Biff still is around the family... as some kind of friend! They even acknowledge if it weren't for Biff being a jerk and an almost rapist, they wouldn't be together.
I don't think Biff is a "friend" of the Mc Flys'. He's only there to work on their cars, as part of his auto-detailing job. Biff's just being a massive suck-up to everyone because he's terrified of George now, and is thus trying to be on his best behavior around him.
In the 1985-A of Part II, they're married and there's obviously no love lost between them. When Lorraine-A tries to leave, Biff-A threatens her kids, which means he's been holding that over her head. In other words, he's been raping her since they got married.
Also, Lorraine-A says to Marty "Oh, they must've hit you hard on the head this time", making us realize how particularly horrible Marty-A's childhood must have been in this time.
To take this one step further: don't forget that the Biff of 1985-A murdered George McFly in 1973-A. It's entirely possible that Lorraine witnessed this, and was finally coerced into marrying Biff (and prevented from reporting him to the police) by the threat that either she or one of her children may be next. What a charming guy.
Looking at her reaction during the newsreel, Lorraine isn't exactly a beaming bride.
After Marty learned his lesson in the past in Part III, he decides not to race with Needles just because he called him "chicken", and thus prevents the accident that would ruin his life. Nice aesop about ignoring jerks who can get you into trouble, right? Until you realize that, according to Marty's mom in 2015, Jennifer probably married Marty just because she felt sorry for him after the accident, which can mean that in this new timeline Marty Jr. and Marlene could as well never have been born...
Or Jennifer could have a higher respect for Marty and his own change. Or her knowledge of time travel and having kids in the future influencing her decision to marry him.
Take it another step forward. In the original timeline, Lorraine is really adamant against girls being the pursuers of men because "they're just asking for trouble." Lorraine of the original timeline may have been raped by Biff as well.
Fridge Brilliance: It's like how George and Lorraine met. Originally, Lorraine only fell in love with Marty's father because he was run over by a car, but in the end she falls for him anyways even though he was never hit.
Or that Marty becomes a Rock God.
Yes, Jennifer felt sorry for the Marty who constantly pitied himself after the accident, but she genuinely loves the Marty we know who doesn't race with Needles.
The Telltale game implies that they're still together at least in 2011.
In the directors commentary of the first film, it was up to Lorraine, not Marty, to stop the near squicktastic Oedipal canoodling between them while they were in the car before the prom. That means if she kissed Marty and it didn't feel like it was "kissing her brother", Biff never approached the car for the attempted rape, and George never came over to the car, either Marty would have (willingly mind you) gone into some serious Philip J. Fry levels of "Pastnastification" in which 2 things could have happened.
He suddenly has a older brother/sister he never had before or...
Fun Fact: The only reason this didn't even remotely happen in the film is that Disney was one of the film's main producers.
Marty never would have slept with his own mother. Maybe the reason it was up to Lorraine to stop things between them was just because if Marty turned her down she wouldn't have gotten over him and wouldn't have been open to a relationship with George. Lorraine on her own had to realize that dating Marty was not a good idea so she could move on.
That's also a case of Fridge Brilliance: People have the ability to unconsciously detect the genetic viability of potential offspring in another person. Sometimes it's by way of pheromones and other times by saliva. This is one reason why two people in Real Life just might not be the right "type" for each other. So, when Lorraine kisses Marty, she gets biologically "turned-off" because she senses his genetic material mixing with hers wouldn't make for a very healthy kid.
Maybe some people have that ability, but surely not all. There have been cases where siblings were separated at a young age, then later met as strangers, fell in love, and got married. And they didn't realize anything was wrong until years later when they decided to trace their family histories...
This is more of a call back to Lorraine's apparently oft-retold story about how she knew George was the man for her when she kissed him. Since that was true in both timelines, kissing Marty may have given her a strong signal it would end badly. They padded it with a joke the audience was in on with the brother bit.
O.K., here's a pretty good one I noticed after my 9000th viewing of Back to the Future. You know how people ask if "You kiss your mother with that mouth?" when you swear? Well, early in the first movie when the McFlys are eating dinner, Marty's brother Dave lets out a loud "Damn!" when he realized he was late for work. His mother then proceeded tell him not to swear and then asked him for a kiss on the cheek.
Marty's mom asks his brother to "kiss your mother before you go". She means a kiss on the cheek, of course. Later, in 1955, Marty gets an actual kiss from his mother.
The "lithium mode on" scene in BTTF 2. Marty activates it and blames his kids for turning it off. From this article on The Other Wiki, we can infer that "lithium mode" consisted in dissolving lithium salts into the household water supply, which Marty used to treat himself. His kids did not need it, but they were forced to drink lithiated water anyway, which affected their brain chemistry and turned their behavior into what we see in the movie. They deactivated lithium mode because they wanted to snap out of it and be normal, but their father won't let them because he only thinks about his own needs.
Or it's pumping lithium, an anti-depressant, through the air-conditioning. Given how crappy Future!Marty and Jennifer's lives are (Jennifer herself is often "tranqued") you can see they'd need it.
In Back to the Future, when Marty returns to 1985, a lot of things are different than when he felt, including his girlfriend's appearance. The meta explanation for this is a simple case of The Other Darrin. However, it becomes horrifying when you consider a possible in-universe explanation. What if his own parents weren't the only teenage couple whose meeting Marty disrupted? Maybe, during the chase with Biff or the Johnny B. Goode recital, Jennifer's parents were in the crowd and were too busy watching Marty to meet each other? Than, at a later time, one parent or the other got married to someone else and had a daughter named Jennifer with them. So the reason Jennifer looks different when Marty gets back is that she has one different parent than before, and is essentially a completely different person.
But they both happen to look just like Claudia Wells?
Since the second Jennifer had one parent in common with the first one, it makes sense that she would look similar.
There are fully armed Libyan terrorists freely driving around America. Fully armed Libyan terrorists planning to build a dirty bomb and who were in no way defeated by the end of the movie.
Not defeated? They crashed into a Photofox kiosk which collapsed around their vehicle. They're going nowhere until the cops arrive. It's all good.
Speaking of which, a man in possession of stolen nuclear material has plenty of time to casually pack his bags for a trip after a gun battle at the local mall?
Here's the REAL Fridge Horror - Remember that scene where Biff is trying to date rape Marty's (future) mom? And George is supposed to stop it? Remember Biff tells him to shut the door and walk away? Okay, now remember the only reason he comes back is because Marty told him to fight for his woman? So what do you think happened in the original timeline when he was still a wuss? I thought of this AFTER I saw the movie back in the 80s, and why I can't watch it even now.
Rest easy. In the original timeline, Marty wouldn't have been there to stage a groping, and Lorraine wouldn't have been parking in the first place. She'd have been inside with George, surrounded by other students, while Biff would still have been outside. Even if she WAS in the car, Biff didn't even see her at first; he was only after Marty, who was again not there in the original timeline. Crisis averted.
In the second movie, after Marty and Doc have returned to their drastically altered future, where Hill Valley is overrun with crime, Marty places Jennifer on the porch of her house. Before leaving, he comments that there are bars on her windows, something that probably wasn't there before. We later find out that Marty's house is no longer owned by his family. So why would Jennifer's house still be owned by her family in this timeline? For all we know, Marty just put her on the front porch of a house full of serial killers and date rapists. Who knows what happened to her in between the time they dropped her off and came back.
Marty has kind of an "oh shit" moment regarding this in the movie. Whatever happened, she was still on the porch and asleep and unharmed by the time Marty came to pick her up. Considering that only a few minutes had passed for her, and that the timeline had caught up with her across the transition from Hell Valley '85 back to it's proper state, nothing happened because whatever horrifying things would have happened to her were averted before they could actually transpire. What WOULD have happened, if "Hell Valley" had gone along unchecked, is probably better left to terrifying fanfiction.
When Marty accidentally prevented his parents from falling in love, they probably would have both gone off to marry other people, meaning that Marty erased at least two other children from time itself in order to ensure his own existence.
People can get married and not have children, y'know, the wedding isn't what makes the babies. Not to mention that Lorraine at least would probably have ended up marrying Biff if Marty hadn't gotten his folks back together.
Even if it's true that George and Lorraine married other people and each had at least one child, there were at least three children who were not born because of this. And if the people they married were supposed to marry and have children with someone else then that's more children that don't exist. And the original spouse of the people who now married George and Lorraine might have married people who were supposed to marry someone else and have children themselves and so on and so on. Who knows how many people might suddenly have not existed because George and Lorraine didn't get together? And there's no reason to think that it better to let the alternate universe children exist at the cost of all the original universe children.
Plus, we can probably forgive Marty for being more concerned over the fate of his own actual siblings rather than hypothetical alternative history children who may-or-may-not exist in some alternative future he's not even aware of. The guy has trouble thinking fourth dimensionally at the best of times, and he doesn't learn that changing the past creates alternative futures for proper until the next movie.
During the course of the Telltale games, Doc is erased from time, and Hill Valley is both turned into a dystopian police state AND wiped from the map.. This means that Marty is the only original human being left in time. (We can be generous and say the rest of the world wasn't terribly affected, but given that Hill Valley was relocated in one timeline, and the lengthy span of time involved, not affecting anything outside of Hill Valley becomes less likely.) Technically, nobody is exactly who he knows anymore... And how the hell is he supposed to know what his timeline-native self did up to the point he returned. I don't know about anyone else, but this is pretty horrifying. - Alphacat
2015 has no lawyers. Yes, it's a funny joke about the legal system, but think about it. Marty's son got ten years for being caught breaking and entering. Suddenly 2015 looks a whole lot less fantastic when you realize you can get arrested for practically anything and worst of all, even if you are innocent, you have NO chance of being either defended or acquitted.
Made far worse. Sure Griff's a major butthead, but petty vandalism, assault (given that a number of people saw him trying to hit Marty with a baseball bat), coupled with destruction of a historic monument as it's the Courthouse-Mall window's he went through? What was HIS sentence?! Did he deserve that fate?
Well, at least in Griff's case, yeah, he probably did. Everything he could have gotten arrested for, he actually did do, and he only did those things because he was so dedicated to cowing Marty (Jr.) that he resorted to physical violence in public. As to getting arrested for anything, the police actually find Jennifer and assume she's a drug addict, and only react by bringing her home without even patting her down. Maybe the future justice system has no lawyers, but there are stricter protocols on when a person can or can't be taken into police custody?
Or it's not illegal to use the drugs Jennifer was using. Given the recent developments in legalization of marijuana in our world, that's fairly plausible.
I would like to make a point about the "Having NO chance of being either defended or acquitted." comment. I would imagine that people would still be allowed to defend themselves in a court of law, but Marty Jr being... well him obviously wouldn't be able to make a very good case.
In the Telltale Games, the Citizen Brown episode, Marty tells Citizen Brown that he was supposed to invent the time machine. His reaction isn't that bad; he's sceptical at first and tries to help him later on. But imagine this: You live your life, doing what you do, and suddenly someone presents you with evidence that you wasted your life, you could have done way more with what you were given, your entire existence is a mistake. He takes it surprisingly well and even manages to do what he was supposed to do, but really, how likely is it that Doc could invent time travel in half a year, when it took the movie Doc, who even had the opportunity to study the time machine, 30 years? This is kind of hinted at in Episode 4, when the ethics of personality overriding is discussed, but I think this would be a lot more horrific than it is portrayed in the game.
We all know how much of a Crapsack World Biff made when he screwed with history. Imagine if the Libyans discovered the time machine...
Actually probably nothing. There really is no conceivable reason why they would get in that car and speed off at 88 MPH instead off just taking back the plutonium and escaping in their van. And even if they did its very likely they would have been shot pretty quickly in 1955 - maybe even by Old Man Peabody given how he was packing a shotgun and had the element of surprise.
In order to have got into the USA without attracting too much attention, at least some of them would have had to know English. If one of them had, say, looked at the little notebook Doc was scribbling on, or noticed the big "Destination Time" and "Last Time Departed From" inside the car, well, there were four Libyans, and they had an assault rifle and a rocket launcher. They could have caused serious havoc in 1955, and that's assuming they didn't deliberately go further back in time...
In the third movie, Marty and Doc learn that Doc will die of a gunshot wound on September 5th 1885. They assume that he will be shot on September 5th. However, it transpires that Doc would actually have been shot on September 3rd, and took two days to bleed out; it's not lingered on, but some thought about this suggests that in the original timeline, Doc's death was long, lingering, painful, and at the mercy of less-than-spectacular late nineteenth-century Old West medical practices.
Word of God in the DVD Commentary says pretty much that, omitting only the "less-than-spectacular late nineteenth-century Old West medical practices" part.
"Lorraine, if you ever have a kid who acts like that, I'll disown you." So.... did Lorraine ever get disowned?
A couple possibilities: in the original timeline, Dad never said that. In the new timeline, he may have disowned her, he may have forgotten, he may have changed his mind, or maybe the kid doesn't quite act like that. A question for the Fan Fic authors.
Dad was reacting to the fact that Marty was making anachronistic references he didn't understand (John F. Kennedy Drive, reruns, etc.), leading him to think Marty was an idiot. Since he was misunderstanding him, we can't conclude he would necessarily have disliked the Marty of the future, in his own time.
Plus, there is such a thing as hyperbole. Gramps is probably just stressing to Lorraine that if her kid grows up to be a weirdo, he's not gonna be happy.
Marty's near-hanging in Part III is extremely terrifying in many ways. First, it's established that the newspapers stopped keeping track of Buford Tannen's kills, so if Marty died, nobody would know about it. Second, on a meta-level, Michael J. Fox himself nearly got hanged for real shooting the scene. On top of that, he'd just had his first child, and his father died during shooting (production was stopped so that Fox could attend his funeral), so his newborn child could've lost his father and his grandfather within months of each other.
In the first film, the 1955 Doc is amazed to find out an invention of his, namely the time machine, actually materialized and works in the future. Then in Part III, after he successfully uses it himself to send Marty back to 1985, he discovers a letter by his 1985 self explicitly telling Marty to destroy it immediately after returning to 1985 himself. It had to have shocked him that he'd go from pride to regret over the time machine.