These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
"Back In Time," "Power Of Love," and especially "Doubleback" deserve special mention!
And "Johnny B. Goode" too. "Earth Angel" as well: doubles as Heartwarming Music.
Alan Silvestri's score for the train sequence in Part III is nothing short of brilliant. It uses the standard BTTF leitmotifs as a baseline; it throws in a drum beat that sounds like a train chugging; it intertwines the action themes, the tense themes, the love themes, the Western themes; and it ends with pure power.
Better on DVD: Parts II and III actually make greater sense when watched back-to-back.
Some Anvils Need to Be Dropped: The "Don't let your Pride get the best of you" aesop they drill into your ahead in Parts 2 and 3. It's Anvilicious but it is surprising how may people actually do put themselves into situations just to prove themselves to others.
Visual Effects of Awesome: The Time Machine itself, from the fire trails to taking off into the sky at the end of the first film. The second movie pioneered a computer controlled camera to make complicated panning shots with Michael J. Fox playing three roles at a time, and you can't tell any difference.
What Do You Mean, It's for Kids?: Remember the joy of watching these films when you were a kid? Remember the scene where the second lead is gunned down by Libyan terrorists? They sure don't make 'em like they used to. On the other hand, when Marty found himself in 1955, he made it a point to try and save Doc from his future fate... and succeeds; it was more of an extremely delayed Disney Death. There's also Marty's plan to get George and Lorraine together at the dance involved him faking a rape attempt on his own mother, which was then broken up by a real rape attempt from Biff.
"If my calculations are correct, when this baby hits 88 miles per hour, you're gonna see some serious shit!"
As such, it was refreshing to see that line appear in the Telltale video game intact.
The first sequel isn't much better, starting with a Groin Attack on Marty Junior. Of course, the cherry on top is the alternate 1985 where Biff is a Corrupt Corporate Executive who murdered George in cold blood, forced Lorraine into marriage and breast implants, sits in a jacuzzi with naked women, and has turned Hill Valley into a hellhole.
Part III has Buford hanging Marty, threatening Clara with rape, and attempting a slow death by bullet on Doc. Plus there's Doc's (implied) one night stand with Clara.
Amusingly, this trope was why Disney turned down the first film, as they thought it was too raunchy, whereas many other studios thought it wasn't raunchy enough (this was the time of teen sex comedies like Porky's and Revenge of the Nerds).
Angst? What Angst?: Marty's mother pretty much shrugs off her Attempted Rape, and the fact that the man who attempted to rape her is working for the family thirty years later doesn't seem to cause her any noticeable distress.
Before he was going to travel 25 years into the future by himself, Doc mentions that he'd get to find out who'd win the next 25 World Series games. Then in Part II, we see the horrific results of someone using future sports knowledge.
Genius Bonus: Biff and his goons are very intimidated by the Starlighters, saying "We don't want to mess with no reefer addicts." To many viewers, knowing that marijuana is not addictive and does not cause violent behavior, this may make them seem like cowards. Those familiar with the time period, though, will know that it was the era of Reefer Madness and the goons had just bought into the propaganda. May double as a Parental Bonus.
The angry Libyan terrorists shooting Doc Brown are less funny after the West Berlin disco bombing of 1986 and the bombing of Pan-Am flight 103 in 1989, both committed directly by or on orders of the Libyan government,
In the "Making Of" documentary, Michael J. Fox expresses interest in traveling back in time to become a cowboy. Then, in Part III...
Doc says his DeLorean is electrically powered. In canon, this is non-sense because you can clearly hear an internal combustion engine which sometimes fails to start up. The need for gasoline becomes a plot point in the third movie. Fast forward to October 2011 when the DeLorean Motor Company announces the DMCEV which actually is electrically powered. It runs on batteries instead of a 1.21GW nuclear reactor, though.
Sacred Cow: Regardless of people's opinions of the later movies, the first is widely regarded as one of the best time travel movies of all time.
Sleeper Hit: No one expected the movie to become as big as it did. Robert Zemekis openly admitted he was just hoping it would break even and the final bit with the Delorean flying and "something's got to be done about your kids!" was meant as a joke on Marty having just changed the past for his parents. Fox recalled being informed about the movie being a hit and was pleased, but they had to reiterate that it was a BIG hit.
Special Effect Failure: The Bobs were never thrilled with the effect used to show Marty's hand fading from existence.
They Just Didn't Care: Not the movie, but the 2010 HD transfer used on the Blu-ray and re-released DVD. (Like Digital Destruction, too, but minus the "digital" part.) The end credits are totally messed up: three-fourths the width they should be, way off-center, and listing to the left. It's as if the scanner was bumped out of alignment and something tried to autocorrect it without any human noticing. Those who recall Parts II and III getting misframed DVDs in 2002 may be wondering if Universal Studios Home Entertainment can get anything right; however, unlike that case, they're not fixing anything, and refuse to admit it's even wrong, over two years later.
Big Lipped Alligator Moment: What exactly WAS the point of Marty and Doc running back and forth on an empty road at night when they'd gone back to 1955 again and Doc was explaining their plan? Couldn't he have just told Marty what they needed to do while standing still?
Harsher in Hindsight: In Part II, the USA Today in 2015 talks of the U.S. preparing for Queen Diana's visit. Unfortunately, in 2015, she will have been dead for 18 years. Then again, that also assumes Elizabeth II isn't around in 2015. As of 2014, she still is.
As mentioned in the example for the first movie, seeing an aged-looking Michael J. Fox struggling with his guitar might be a bit disconcerting to watch.
Heartwarming In Hindsight: The McFlys, apparently an average suburban American family in 2015, can still manage to find time to eat a (re-hydrated) pizza together. Yes it's the setup for an Acting For Three situation; no that doesn't detract.
Even though Japan Takes Over the World by 2015, the Toyota (formerly Studebaker) dealership bizarrely now sells Pontiacs. Pontiac folded in 2009. However, before Pontiac went under, they did the Matrix/Vibe crossover car project... with Toyota. Zemeckis was in the ballpark...
When Marty first arrives back in the alternate 1985, he tries to enter his bedroom through the window and crawl into his bed, only to find out that an African-American family is now living in his house and is none too pleased with their bedroom intruder. This was kind of funny originally, but has become absolutely hilarious due to the similarities between it and a memetically mutated bedroom intruder incident. Yes, Marty's climbin' in yo windows, he's snatching yo people up.
Also, one of the newspaper's "Newsline" items refers to a female President. The way things are shaping up, that can only mean one thing...
Now that Obama's been elected to a second term, the only way there'll be a female President in 2015 will be if Obama and enough male people in the presidential line of succession died. Or if there's some sort of coup d'etat between now and then.
As of 2012, just three years before the fictional setting in the movie, there IS now an MLB team that adopted Miami into its name.
The thought of videogames with handheld controllers becoming considered as lame as "a baby's toy" could easily come true after the release of the Kinect.
Magnificent Bastard: Biff. He may not be too smart, but with one simple plan from an older (and more experienced) Biff to help his younger self, he starts an empire from successful "gambling" that allows him to start several companies (most highly nuclear power plants that generate enough pollutant to require a waste reclamation sub-industry; hmmm). Considering how he claims he "owns the police," he can certainly manipulate a lot, and he's definitely a bastard.
"Shark still looks fake", is a frequent snark used when watching the Jaws films.
Moral Event Horizon: Biff himself definitely crosses it when he kills George and becomes Lorraine's abusive rapist husband after becoming rich through the Gray's Sports Almanac. Even though this is an alternate timeline that is later rectified, knowing that he even had the potential for it is enough. Thankfully, in the actual timeline he doesn't stoop to such lows.
Newer Than They Think: Although it seems like hoverboards should be a staple of sci-fi as old as jetpacks and flying cars, which have both been in stories since at least the 1930s, this is actually what introduced them.
This might have something to do with skateboards in general being Newer Than They Think, with short skateboards like the one Marty rides gaining popularity in the late 1970's.
Special Effects Failure: All the scenes of past and present characters interacting with each other were well done, except when 1955 Biff tosses the sports almanac to 2015 Biff in his garage.
Critical Research Failure: a major plot point has Clara and Doc bonding over their love of Jules Verne literature. Then, when he says he has to leave because he's a time traveler, she believes the story is just him taking her love of Verne books to make up an insulting BS excuse for why he's leaving her. Except The Time Machine was by H. G. Wells, not Jules Verne. Verne never wrote a time travel plot in his entire career, and she would have known that.
Genius Bonus: When the Colt salesman tries to get Marty to shoot the Peacemaker, he forces it into his left-hand (causing the first shot to miss completely, being Marty's weak hand). The Colt Single Action Army was actually originally designed to be fired left-handed while riding a horse.
Marty uses a Frisbie pie tin like a Frisbee. This actually is how the toy was invented and got that name.
Moral Event Horizon: This trope caused a scene to be removed from the film. Originally, the movie was to have contained a scene where Buford Tannen, ancestor of Biff, shoots and kills Marshall Strickland in front of the lawman's son. According to screenwriter Bob Gale, the scene was removed because it was felt that after Buford is seen committing such a deed, it doesn't seem right that he not die (and he can't die, seeing as he will need to live long enough to extend the family line).
The scene made it into the novelization of the movie, however. And the Marshall's son grew up with a strong sense of discipline, and made sure it got instilled in all his kids. So Buford just made life hell for all his descendants in general, and Biff in particular.
It's also referenced and possibly canonised in the Telltale Games sequel.
Relationship Sue: Clara, to her detractors. Who would believe a woman in her 30s and a man in his 60s could fall instantly in love? Clara's main purpose is to be Doc's love interest and drive his decisions, thus influencing the outcome of the plot.
Strangled by the Red String: The film discusses this in regards to Doc and Clara's relationship. After going back to 1885, Marty shows Doc a picture of his future tombstone, which contains a mention of "his beloved Clara", though Doc doesn't know who she is, even though he's supposed to be killed in three days. After finding out who Clara is and that he's supposed to be meeting her Doc and Marty discuss it. Marty believes it's possible, but Doc, being a man of science, refuses.
Marty: Well, Doc, now we know who Clara is.
Doc: Marty. It's impossible. The idea that I could fall in Love at First Sight? It's romantic nonsense. There's no scientific rationale to that.
Marty: (Laughing) C'mon, Doc, it's not science. You meet the right girl, it just hits ya; it's like lightning.
Harsher in Hindsight: The direct-to-video special The Secrets of the Back to the Future Trilogy plugs Back to the Future: The Ride when Kirk Cameron informs a young boy that Universal will not make a Back to the Future Part IV, but the series will "live on" through the ride.
The Pop-Up Trivia track on the Back to the Future Part III DVD ends with a similar plug.
Accidental Aesop: The ending of Episode 5 is sort of the logical conclusion to the entire series and films. Screwing around with the timeline keeps fucking things up til you have three older Marty's begging young Marty for help, all from different timelines. At that point, Doc just shrugs and tells Marty to ignore them. Now is important.
It's actually brought up several times throughout all five episodes.
Broken Base: There is a certain friction that occurs between those who are longtime fans of the Back to the Future franchise and those who are longtime fans of the Telltale Games company.
Jerkass Woobie: Even after everything, it's hard not to feel kinda bad for 1931!Edna when Marty breaks her up with Emmett.
Just Here for the Plot: Many non-gamers have taken interest in the game strictly for the Back to the Future story line — much to the chagrin of the more avid gamers who are, overall, disappointed with the game play of the series.
The Scrappy: Edna Strickland, though this is intentional.
The Woobie: The Citizen Brown timeline in Episode 3. Everyone seems on the verge of a nervous crackup due to the Dystopia of alternate Hill Valley, Marty seems like he's panicking about 86% of the time, and the only halfway normal person is a Delinquent who would probably be a child psychologist's field day. Even Brown himself comes off as a Tragic Hero.