27. THAT FANTASTIC STORY IS REAL.
The issue of Fantastic Story Magazine we see next to a sleeping George when Marty wakes him up as Darth Vader from the Planet Vulcan is genuine: It’s the Fall 1954 issue. It cost 25 cents. Marty’s yellow alien getup will eventually inspire the cover art character for George’s 1985 book, “A Match Made in Space.”
28. (EDWARD) VAN HALEN IS ACTUALLY PLAYING THE GUITAR.
The tape Marty uses to scare George is an actual uncredited solo by guitarist Eddie Van Halen. The band Van Halen wouldn’t allow their name or music to be used in the film (thus the added “Edward” on the label), but the guitarist allegedly gave Zemeckis an outtake to use from a song called “Donut City” he created for the score for the 1984 film The Wild Life.
29. BIFF AND HIS ANCESTORS ARE USED TO MANURE THROUGH THE AGES.
The Statlers aren’t the only multi-generational small business owners in Hill Valley. Biff has run-ins with D. Jones Manure Hauling trucks in 1955 in the original movie and Part II, while Mad Dog Tannen falls into an A. Jones Manure Hauling truck in 1885 in Part III.
30. DOC NEVER BUILDS HIS MODELS TO SCALE.
When Doc runs Marty through his time machine plan with models in the garage in his 1955 garage laboratory, he says, “I didn't have time to build it to scale.” When Doc says the same line in Part III (with the same car toy model), Marty finishes his sentence by saying, “Yeah, I know, Doc. It’s not to scale.”
31. DOC’S INJURIES ARE IMPORTANT TO TIME TRAVEL.
The bandage on Doc’s forehead when Marty shows up to his house in 1955 is from his eureka moment of his idea of the Flux Capacitor when he fell and hit his head in the bathroom while hanging a clock. The toilet is later seen in Part II when Marty returns to 1955 for the second time.
32. DOC SPENT A LOT OF TIME ON HIS OTHER INVENTION THAT DIDN’T WORK.
The time machine wasn’t Doc’s only invention. Schematics for Doc’s faulty brainwave machine can be seen strewn across his house and garage. Marty later wears Doc’s brainwave machine in Part III.
33. THAT MAN ON THE BIKE MIGHT LOOK FAMILIAR.
The guy riding by Doc and Marty in 1955 as the former tells him not to tell him what happens in the future just before the lightning storm looks kind of like Doc...because he is Doc. This is 1985 Doc Brown who meets his younger self in Part II.
34. MARTY MIMICS MORE THAN JUST CHUCK BERRY AT THE ENCHANTMENT UNDER THE SEA DANCE.
Marty essentially invents rock ‘n roll music by mimicking Chuck Berry to his fictional cousin, Marvin Berry. But he also shocks the teeny boppers of 1955 Hill Valley by kicking over the speakers as a homage to The Who’s Pete Townshend, and he also plays his guitar lying down like Angus Young of AC/DC.
35. SOMEONE REALLY NEEDS TO FIX THE DELOREAN’S STARTER.
When he gets to 1955, Marty has to get rid of the DeLorean because, as he tells Doc, “Something [was] wrong with the starter, so I hid it.” This explains why the DeLorean suddenly stops working just as he’s about to go back to the future in the climax of the movie.
36. MARTY REMEMBERS DOC’S BULLETPROOF VEST TRICK.
Doc reads Marty’s ripped-up note in 1955, knowing he’ll die in 1985 unless he wears a bulletproof vest against the Libyans. Doc’s life-saving vest maneuver foreshadows Marty’s own makeshift bulletproof vest (made out of an iron stove cover) in Part III.
37. THE CLOCKTOWER LEDGE IS A LITTLE WORSE FOR WEAR.
Doc does permanent damage to the clocktower ledge during the lightning storm in 1955, which wasn’t there in the initial 1985 timeline, but can be seen still damaged in the improved 1985 at the end of the movie.