Many superhero comics. Superman was a Flying Brick who couldn't fly, only jump (hence, "able to leap tall buildings in a single bound") and run (hence, "faster than a speeding bullet"); Batman and the Teenage Mutant Ninja Turtles both killed their adversaries, even Joker and Shredder.
During the early years, DC's different heroes very clearly took place in separate continuities - an issue of Batman from the 40s, for instance, had Dick Grayson get an autograph from Jerry Siegel, identified by name and explicitly noted as "the creator of Superman".
Early Timely (Marvel) Comics did the same. In the very first Captain America story, the Human Torch is mentioned as being "a hero from the comic books". About a year later, Cap and the Torch met in a crossover story.
Superman was probably the most notably different of these lacking many of his current powers, sporting a different (and often inconsistently illustrated) costume, killing bad guys, and being something of a rebel. But especially weird, given his current international sensibilities, is when we're told that "Superman says 'You Can Slap a Jap'" as seen on many World War 2 era covers.
In part this is because Superman, Batman, and some of the others listed here were introduced before the genre was codified as they were the codifiers of many of its tropes. Their early adventures were the Early Installment Weirdness of the entire genre. Another major reason is because of The Comics Code; for a significant length of time, comics simply couldn't have their main characters kill people, so they gave them Technical Pacifist leanings (and made them more like The Cape in general) as a way of satisfying Moral Guardians. These characterizations were used long enough to stick after the Comics Code fell.
Superman wasn't always the well meaning hero he's known as today. In fact, he caused more harm than good in his earlier comics, and was actually kind of nuts. Examples include deliberately trapping a party of rich people in a mine to demonstrate the mine's safety problems, and drugging a football player and taking his place on the team, so that an opposing coach, who is guilty of cheating, won't win. He also once tackled teenage delinquency by demolishing their slummy neighborhood, making sure that the residents had evacuated with their possessions, upon learning that the government would be obligated to rebuild the neighborhood.
Clark Kent and Lois Lane didn't originally work for the Daily Planet in the fictional Metropolis. Instead, they worked for the Evening News in Cleveland, Ohio.
Lex Luthor used to be a typical Mad Scientist who used his skills to commit crimes, rather than a Corrupt Corporate Executive who moonlights as a supervillain. His motivation for battling Superman was also a lot less complex and more petty, essentially amounting to "I'm bald because of you! SCREW YOU!".
Batman was perfectly willing to kill in his earliest appearances, as seen in his very first story, where he punches the villain into a vat of Hollywood Acid, and shows no remorse for it.
Readers weren't told about the death of Bruce Wayne's parents for the first 6 months of the character's adventures. These early adventures took place in New York City rather than the fictional Gotham. Also, he had purple gloves.
Bruce Wayne originally had no servants in his home, unable to trust anyone with his secret identity (except Robin, once he showed up). When Alfred was introduced (4 years after Batman's debut in Detective) he was a bumbling comic relief character who looked and acted almost completely different from the man we know.
A lot of Batman's Rogues Gallery were completely different in their initial appearances:
The Joker originally had No Sense of Humor. His Silver Age self was closer to his typical depiction but was simply an affable, legitimately funny thief who liked to make people laugh and viewed Batman as a Worthy Opponent; a far-cry from the creepy, murderous psychopath he would become famous as. He would even sometimes team-up with the heroes to take down worse villains, such as a memorable issue where circumstances forced him and Superman to work together in order to save Perry White.
The Scarecrow was originally a standard hoodlum-for-hire (albeit one who used to be a college professor) who terrorized his victims the old-fashioned way: with guns and death threats (in this era, fear gas was actually the gimmick of the now-comparatively obscure Hugo Strange). He also managed to hold his own against Batman and Robin physically, at least for a little while.
Clayface used to be a simple thief/murderer without superpowers who wore an old costume. He only got the upgrade to superpowers after it became clear that Batman and company completely outclassed him.
Mr. Freeze, one of the most famous examples of the Tragic Villain, was originally just your typical bank-robbing supercrook who cracked jokes and used cool Sci-Fi weaponry to pull off heists. Also his condition didn't change his physical appearance, he called himself "Mr. Zero", and his freeze-gun couldn't kill people. It wasn't until Batman: The Animated Series revamped the character that he became the pitiable and tragic character he's famous as.
Poison Ivy's debut contained none of the Gaia's Vengeance or Straw Feminist themes the character would later become famous for; her association with plants only went gimmick-deep, and even then it was largely metaphorical (she got into crime because she was a huge Attention Whore, who sought to stick in the public's mind like a case of poison ivy).
The modern version of Batwoman debuted in the series 52, with a different look than what she'd sport in her ongoing series and Detective Comics appearances. Kate was first depicted as having long auburn-red hair, was more into dresses for her fashion sense, and had brown eyes. When her series came around, her skin was dramatically lightened to be a "vampire porcelain white" (to better reflect a redhead's complexion), she was depicted as dressing more punkish, her hair became short and a highly saturated shade of red, and her eyes were changed to green.
She was also portrayed as a closeted Lipstick Lesbian, in contrast to her depiction in Detective, where she sports a more masculine dress style and is open about her sexuality.
Lots of members of the Justice Society of America were completely different. In fact, Pre-Crisis, many "modern" superheroes like Batman and Superman coexisted with them and were members of the team rather than its successors. These differences and changes were either retconned away or explained as having been a previous member who retired or died during the timespan between the JSA's initial disbanding and the formation of the Justice League. To whit:
The first Atom didn't have the character's signature size-changing powers, just Super Strength and an "atomic punch". His costume was also totally different, with a yellow shirt and a cape.
Originally Doctor Fate's magic wasn't based on Order, as it would be for many years post-Crisis; it was merely general spiritual power. This extended to his archenemy Mordru, whose powers weren't based in chaos and who wasn't immortal.
Hourman'sSuper Serum used to be completely beneficial and harmless, in stark contrast to how it would later be portrayed (addictive and dangerous, with Hourman taking years to overcome it and create a non-harmful version).
The Spectre was actually a member at one time and not only that, but he was just a fairly typical superhero. No horrific murdering of criminals, no inability to understand mortals, and he and Jim Corrigan were the same person, not two separate entities sharing a body.
The first Black Canary didn't have the famous sonic scream power.
Atom Smasher used to call himself Nuklon, and his hair was cherry red rather than darkish brown. Also he had a Mohawk. Yes it was exactly as ridiculous as it sounds (it actually became something of a Running Gag for the series, with nobody letting Al live it down).
The first Red Tornado is probably the most striking example. For one thing, it was a woman posing as a man and she was completely human rather than an android. She also didn't really have that much red on her costume and had no superpowers or gadgets to speak of, relying on her own wits and strength.
Early comics had trouble defining what exactly his "spider sense" is and how it works. In one early comic, he was able to use it to "tune in" on the Chameleon's location (clear across New York City in a helicopter) and in another, Doctor Doom was able to use it like a radio signal, transmitting a message directly to Spider-Man using some kind of transmitter hooked up to a spider. (To this day, it's still a bit vaguely defined. The Spider-Girl comics showed his daughter, having developed her powers earlier, being able to use her spider sense in a few ways her father can't, such as being able to pinpoint the exact source of the danger in a way that sometimes allows her to find a vulnerability in an enemy.)
The character of Gwen Stacy was radically different in her earlier depictions. Initially she was depicted as a Tsundere type character for Peter Parker, berating and mocking him for his "lack of manliness" but still feeling some innate attraction to him that she couldn't describe. Her character mellowed out later on, becoming far more emotional and with less of a hard edged personality. The introduction of MJ also saw several aspects of her character change- like her hairstyle and her dance moves- to better match the more popular MJ. And for those who are only familiar with her most recent incarnations where Gwen is a scientific equal to Spider-Man, in her initial comic appearances- even up to her death- she was never depicted as having an interest in science and was only Peter's classmate in one class.
The aspect of Venom changed over time as well. Originally, it was just an alien costume with stronger webbing, changing into a symbiote when the costume proved unpopular. The symbiote driving people insane wearing it wasn't even a thing in the comics - that came from Spider-Man: The Animated Series. Venom's design also changed over time as its first appearance had the only major design change being a mouth and a row of teeth. A few appearances later, the teeth got sharper and a tongue got added in.
Before EC Comics made its iconic horror, crime, war and science fiction classics like Tales From The Crypt and Weird Science, and later satirical comics like MAD magazine, its first three years were as a fairly standard comic label called Educational Comics, which had wholesome fare like Picture Stories From The Bible and Animal Fables, the total antithesis of the kind of stories and art that would put EC on the map from 1949 and on.
The Brazilian distributor of Disney Comics released in 2000 a special celebrating the 50th anniversary of their Donald Duck magazine. The description of the first issue listed all that could be found weird: differences in language/spelling (apart from the 1950s version being quite formal, Portuguese underwent several orthographic reforms) and character names (biggest one was Goofy being called Dippy - though the story has him being called "a goofy guy"; in one story, Goofy was discovered by talent scouts after they didn't like his original name, Dippy Dawg), unfinished stories (it was published across 3 issues as movie serials were popular in those days), only eight pages in color, and a trivia section filled with Values Dissonance (telling stories of animals suffering accidents, such as jiraffes being decapitated by telegraphic wires). 10 years later, the collection released to celebrate the 60th anniversary had its first issue come with a facsimile of Donald Duck #1, letting readers experience Early Installment Weirdness firsthand.
The early Sonic the Hedgehog comics were very comedic and often even stranger than what we have today, with lots of fourth wall demolition, Better Than a Bare Bulb, and Hurricane of Puns. This was more due to following Adventures of Sonic the Hedgehog and using a few video game stages in the early days, as well as the fact that Michael Gallagher was the head writer. Sally was seen with varying colors of fur (red fur with blonde hair in her first appearance, pink fur with black hair up until issue 16) and Rotor was known as "Boomer" until about issue 6. Roboticization was shown differently with people with hypnotized eyes instead of out and out robots. The series wouldn't reach the SatAM levels until Dulcy showed up in issue 28 and a few characters will still seem odd looking back at them (for instance, look at Metal Sonic in issue 25 and look at him today). Once Gallagher backed off as head writer, the series began to resemble what it does now.
Sonic the Comic was just as bad. For a while it was full of one-shots that barely related to each other, often with Off Model drawings. It took several issues for it to become plot-orientated, and even afterwards it took a while for it to drop the oneshot routine.
Stan Sakai has stated that he regrets having made Hikiji human.
The first few Hellboy stories are very odd to read in comparison to later installments, thanks to John Byrne's writing. Under Byrne, Hellboy uses a Private Eye Monologue to describe the story, tying him more closely into the Nineties Anti-Hero archetype. When Byrne left and Mike Mignola, the series' creator, took over dialogue in addition to plotting and art, this form of exposition vanished.
In addition, while the comic was always very dark, the first story arc was closer to a straight-up horror comic.
The first two Nemesis the Warlock stories - Terror Tube and Killer Watt - refer to Torquemada as chief of Tube Police, while later he is referred to as "Grand master Of Termight". Nemesis spends both stories inside his ship, with no clue about his identity or appearance, saying nothing but his Catch PhraseCredo!, which he tends to use at odd moments. A lot implies it wasn't even established that Nemesis is even an alien back then, with narration referring to him as "not an ordinary man" at best.
While people often note the various changes that came about when the Teenage Mutant Ninja Turtles changed from being merely a comic book to a multimedia franchise, the original Mirage comics were also subject to quite a bit of this. Most notable is the Frank Miller-esque narration, which was gone by the series' second issue; the idea that the turtles had grown to look like their present-day selves in the space of a year, which was ignored when the writers decided to write stories featuring younger versions of the characters; and the bit where Splinter expressly trained the turtles so they would kill The Shredder for him, which was glossed over with time. The Shredder himself was originally a Token Motivational Nemesis and Starter Villain who died in the end of issue one. He did kill Hamato Yoshi, yes, but he was pretty much the crook who shot Uncle Ben but with a cooler outfit.
The Human Torch looked like a featureless yellow blob of flame, taking after his Golden Age incarnation.
As well as the Thing looking very lumpy and uneven. The rest of the team also called him 'Thing' all the time instead of Ben... which is pretty dickish and insensitive in hindsight.
Doctor Doom acquired the ability to switch minds with whomever he had eye contact with. This is an ability that he occasionally uses even in the newer comics, but it was an odd concept for the time. A later Retcon stated that only his infamous vanity keeps him from using the ability more often.
Furthermore, in Doom's first appearance, he doesn't have the grudge with Reed Richards that has come to define his character - they just happened to be at college at the same. His plot is a little less world-shattering as well - kidnapping the Fantastic Four to STEAL BLACKBEARD'S TREASURE. And he didn't have a cape.
Asbestos was all the rage when it came to thwarting those with fire-based powers. Captain America Comics #63, Invaders #22, and Human Torch Comics #27 have the Asbestos Lady, who wore asbestos lined clothes and fired a gun with asbestos-lined bullets. In Strange Tales #111, the Human Torch fights the Asbestos Man, a chemist who has made a suit and shield of "super-asbestos". The Terrible Trio in Strange Tales #122 captures Johnny Storm with an asbestos rope and blanket, keeping him in an asbestos trailer. In The Avengers #206, The Avengers wear asbestos suits to confront the villain Pyron the Thermal Man.
Human Torch #38: Professor Marko's Hydromatic Vacuum attempts to suck out all the air in the world, and is almost successful as people throughout the world gasp for air.
Ultimate Marvel Team-Up was done very early in the life of the Ultimate universe. As a result, a lot of characters like Hulk and Iron Man appeared before they were given headlining roles in The Ultimates and are noticeably different from what would come.
Early issues of The Ultimates seemed to imply that the Fantastic Four were already around and well-established as heroes before the Ultimates were even formed. Ultimate Fantastic Four contradicted this by showing that the team's origin took place long after the formation of the Ultimates, with the Four themselves reimagined as a group of inexperienced teenagers.
After his first appearance in Tales of Suspense #39, Iron Man spent the next few issues traveling back in time to visit Cleopatra, fighting a robot caveman built by aliens, preventing a race of people who lived inside the Earth from invading the surface world, and having several other wacky adventures. It wasn't until Tales of Suspense #45 (the first appearance of Pepper Potts, Happy Hogan, and supervillain Blizzard) that he started to edge more towards superhero territory.
Similarly, the Martian Manhunter, having first appeared at the start of The Silver Age of Comic Books, was more like a detective than a superhero in his initial appearances and only became a superhero when superheroes started to get popular again.
Also, there was absolutely no indication whatsoever that Mars was a dead planet or that J'onn was the Last of His Kind. Many of the tales of the time feature either Martian technology or the appearance of other Martian characters.
Notably, Bruce Banner originally turned into the Incredible Hulk at night. He was also originally coloured grey, but this changed to green, as grey was hard to reproduce consistently in the 1960's.
Of course, these two traits were notably brought back years later in the 1980's where it was revealed that the Grey Hulk was another personality of Banner's.
There are a lot of other weird things that happen before Hulk hits his stride, him changing via machine, Hulk's intelligence level going up to near Banner and down to inhuman stupidity. The early issues also make the Hulk quite misanthropic (an extremely bad thing when coupled with Banner's brains) and Rick Jones was the Kid with the Leash who kept him from actually trying to end the world at least once. It takes them awhile before the character is associated with anger, around his first visit with The Inhumans where they establish that his strength increases with his rage.
Hulk also had an ever-changing number of toes. When he first appeared, he had five toes. When his book was cancelled and he resurfaced in Fantastic Four, he now had three. When he joined the Avengers, he then had four, but went back to three by the second issue, only for this number to vary wildly in each subsequent appearance before the artists finally settled on five in Tales to Astonish. This was the subject in a Mythology Gag in Ultron Forever, where the Hulk transported from the past still had three toes.
The Hulk being a founding member of The Avengers. It didn't take Stan Lee long to figure out that the Hulk wasn't exactly a team player, such that by the third issue of the series he's actually fighting against the others in full-on supervillain mode. Later comics have dealt with his on-again, off-again membership in all manner of ways as his intelligence has fluctuated.
His trademark Vibranium/Adamantium shield was not originally indestructible. When Cap was first reintroduced in The Avengers during the 60's, Stan Lee tried to make him a little more "super" by having Iron Man outfit the shield with magnets and transistors so that it could be remote controlled. Lee abandoned this idea after a few issues, and instead decided that from then on, the shield would now be impervious to most forms of damage.
The idea that the shield was made of Vibranium and Adamantium is itself a retcon, as Captain America was created decades before either of those fictional metals were introduced in the Marvel Universe. Exactly what the shield was made of wasn't established until many years after Cap's Silver Age revival.
His partner, The Falcon, started off as a Badass Normal with a green costume and no powers or gadgets outside of a grappling hook. His trademark wing suit and red color scheme weren't introduced until a few years after his creation.
When Black Panther first appeared in Fantastic Four, there was no indication that T'Challa wasn't the first person to use the identity, and his origin in general was closer to that of Batman (with T'Challa seemingly creating a costumed identity to avenge his murdered father). It was only years later that it was established that the Black Panther was a Legacy identity, and that T'Challa's father had been the previous hero to use the name.
Upon reading the firstSilver AgeGreen Lantern story, you get the impression that the Green Lantern Corps (referred to only as space-patrolmen in the story) do not generally call themselves Green Lanterns — in fact, "Green Lantern" was only an alias Hal adopts for himself.
The Golden Age Green Lantern, Alan Scott, is quite different from the more famous Silver Age version. He was based out of Gotham, explicitly used magic, had a weakness to wood. He also never had any contact with the rest of the corps, being solo.
Moonstone from the Thunderbolts originally appeared in Captain America as a gun-toting henchwoman for Doctor Faustus. She didn't have any powers, nor were her trademark scheming and manipulative tendencies apparent.
Knights of the Dinner Table: The series started as a comic strip in the back of SHADIS gaming magazine and as such, the character were flat and Sara had not been added yet. The Knights were simple gamer stereotypes shifting to fit the gag of the strip (for example, Dave, Bob and Brian all knowing the stats for a monster whereas in later strips, only Brian had stats and charts memorized like that.)
Healing Factor characters Wolverine, Sabretooth and Deadpool are depicted as sustaining injuries over a length of time in early appearances, compared to later appearances where healing appears near instant. Sabretooth's face was injured in The Spectacular Spider-Man vol. 1 #116 and still scarred by his next appearance in #119. In an X-Force appearance, Deadpool complains his broken jaw left him hospitalized for a few weeks. One can assume characters had weaker healing factors in the past, but newer stories set in the past still depict a near instant healing factor.
This can be applied era to era in comics but especially the Silver Age which generally has the silliest and most over the top plots and really sticks out from the other eras with many of the most popular characters of today being invented or taking on their most recognizable forms in that era.
Both Marvel villains and Iron Man used Hypno Ray technology consisting of swirling spiral patterns and some vaguely defined energy to automatically hypnotize the target.
Magnetism was the force used by Iron Man's repulsor technology, being just as powerful and versatile as Magneto, lifting others by their blood's iron content and juggling cars.
Radiation is ubiquitous when it comes to gaining new super powers, treated as a mysterious magical energy when battling the likes of Radioactive Man, with no indication of radiation's adverse effects. The X-men hint the origin of their mutations are tied to the nuclear bomb tests of the nuclear age, a detail ignored in most modern stories aside from the phrase "of the Atom".
Tales of Suspense #49: "The New Iron Man Meets the Angel!" Witness as Tony Stark (here called Anthony Blake) encounters the Angel! After a nuclear explosion goes off from a Stark Industries atomic bomb test, Iron Man is shielded from the blast by his own armor, saving himself from hitting the ground with his Magnetic Repeller! But not Angel, who becomes evil! Is this a fiendish plot from an evil mutant? No! The radiation convinces Angel he is an Evil Mutant! Angel informs the X-Men he is leaving to become an Evil Mutant since "that's where the action is!" The X-Men use a top-secret device to contact the Avengers "in a secret wavelength used only by the X-Men and other specially licensed crime-fighting organizations". Angel attempts to draw the attention of Evil Mutants by detonating sticks of dynamite in random locations until Iron Man intervenes, then feigns plummeting to death so Angel can change his mind and save him! This heroic act reverses the corrupting effect the radiation had on his personality! (Note: Iron Man is wearing his post The Avengers #2 armor and mentions the X-Men's offer from The Avengers #3, yet the Hulk is still part of the Avengers team in this issue when he should have left by The Avengers #2. So this issue takes place somewhere around then, in reverse order).
The original Archie Comics looked nothing like their more familiar, modern look. It had the more realistic style of most 1940s comics before becoming stylized like it is today. Archies looked more like Alfred E. Neuman than anything. The characters were also younger and it initially lacked the signature Betty and Veronica (Betty was part of the strip since day one, but Veronica did not show up until the fifth or sixth appearance).
The first three issues of Ninja High School were drawn in a somewhat different style from the rest of the series.
The "Locas" stories in Love and Rockets initially had sci-fi elements, but they were soon dropped and the series became very present-day real-life in nature.
Doctor Strange started out looking much older than his eventual appearance, with slanted eyes and vaguely Asian features, and was styled the "Master of Black Magic."
In the first few isues of X-Men, mutants weren't hated and feared, the X-Men were treated as celebrities (the second issue has Angel meet a bunch of fangirls), they had an official government liasion (Fred Duncan), Beast was Dumb Muscle, Iceman was a Jerk Ass (mission briefing would sometimes lead to him attacking the rest of the team) and Jean's telekinesis was for some reason called teleportation, even in the second issue, in which they fought an actual teleporter. Xavier didn't hesitate to hit people who knew too much with Laser-Guided Amnesia, either.
Before he was Wolverine's Arch-Nemesis and one of the X-Men's most iconic baddies, Sabretooth started off as an Iron Fist villain, and not a particularly memorable one at that. He was partnered with Constricter, there were no hints at his mysterious backstory or connection to Wolverine, and he didn't have a healing factor either. He was also much less of a threat, getting his ass handed to him by characters like Black Cat. It wasn't until the 1986 "Mutant Massacre" crossover (Sabretooth was introduced in 1977) that he began to become the villain we know today. It was the first story to have him fight Wolverine on panel, as well as the first one to reference their mysterious shared past. He was also played up as a much more powerful and intimidating character than he'd been previously, and was finally confirmed to possess a healing factor like Logan's. Those early issues are so jarring by comparison that Chris Claremont actually considered Retconning all of Sabretooth's early appearances into clones created by Nathaniel Essex.
In early issues of The Beano pretty much all the comic's most iconic characters had yet to appear. The only strip in the first issue to survive into The Fifties was Lord Snooty. Early issues also included text stories and adventure strips unlike later ones which only featured humourous comic strips.
When Dennis the Menace first appeared in 1951 he lacked his red and black stripey jumper and instead wore a tie.
In the early strips of Mortadelo y Filemón, both worked alone as private detectives instead of being secret agents, Filemón was always angry and smoked a pipe, Mortadelo was even more stupid and clumsy, and there was barely any of the Slapstick that defines the series nowadays.
The series La parejita started in 1993 as "Emilia-o", the story of a 18-year-old couple who had to serve in the Spanish military service. Emilia, the girl, disguised herself as a man to stay with her boyfriend during that time instead of being sent to different destinations. After a year of military jokes, author Manel Fontdevila decided to put the couple back in the city and write a story about their day-to-day life, which he described as "putting the same actors in a different set".
On their very first appearance in "Johan and Peewit: The Flute with Six Holes", The Smurfs had five fingers on each hands, their village was on a rocky, barren landscape and their houses were different sizes and species of mushrooms.
In W.I.T.C.H., Will was a major Butt Monkey and it seemed all she existed for, beyond being leader, was having something horrible happen to her. She lampshades this when her dormouse is ran over after she and her friends save her family's livelihood from her Jerk Ass, gambling-addicted father.
In "Tintin in the Land Of The Soviets" Tintin only gets his famous hairstyle several pages into the story, with the apparent side effect of a car crash being that his hair goes on-model
The early Tintin stories before "The Blue Lotus" are mostly a continuous series of events without much focus and a lot of randomness. "Tintin in the Land Of The Soviets" and "Tintin in Congo" ("Tintin in Africa") are plain propaganda stories warning the youth against Soviet communism and praising the virtues of Belgian colonialism in Congo. Tintin's travels to foreign countries were simply based on stereotypical ideas. Hergé only started doing research for his stories from "The Blue Lotus" on (It's probably worth noting that in "The Blue Lotus" itself he mocks national stereotypes, most notably by having Dupont and Dumond trying to blend in with the locals by dressing up like Fu Manchu).
The first Asterix story, Astérix the Gaul, had a single issue Art Evolution (with plenty of Off Model drawings before Uderzo settled on the style he employed for years to come) and a plot unlike the ones that followed, in particular having a relatively small role for Obelix (who also wears an axe on his belt in this first album). Julius Caesar also looks completely different in this album. Compare the one on the first page with the one on the final pages! And even then he still doesn't resemble the later Caesar!
Most of the Gauls have much longer hair and moustaches.
A single drink of magic potion apparently makes one strong for several hours, whereas in later stories it lasts long enough to see a battle to its end (which are usually pretty brief anyway with the Gauls having the strength to see off any enemy in one hit) but certainly not for hours.
Getafix originally lived in a cave. Fulliautomatix looked radically different, more a roly-poly sort with a long nose rather than broad-shouldered. He shapes iron with his bare hands instead of his trademark hammer.
Cacofonix' outfit is also different. On top of that, the running gag that his music is just horrible isn't yet set up. Asterix refuses to let him sing early on but only because he has better things to do, the Gauls dance to his playing with no complaints, and he sings at the banquet at the end (!!!!), only annoying a couple of characters sitting right next to him, presumably with volume rather than quality.
The first issues also have the lack of Dogmatix before his introduction in Asterix and the Banquet.
The first three Lucky Lukes people and animals are drawn in a more roundish "animated cartoony" style, complete with four fingers one each hand. Comics artist Morris aspired to bring his characters to the screen in an animated form and thus they look more like animated cartoon characters.
Luke in particular has a different outfit and a large chin.
Lucky Luke also shot his opponents dead or wounded them severely. In later stories he simply shoots their weapons out of their hands.
In their first appearance The Daltons were actually shot dead by Lucky Luke! Since the characters proved to be very popular Morris brought them back, or rather their Suspiciously Similar Substitute cousins! So the Daltons we know today are actually copies of the original.
For almost 40 years Lucky Luke was portrayed as a cigarette smoker, something Morris eventually changed under pressure of health groups and fear of children imitating the habit.
In the first official story "Rikki en Wiske in Chocowakije" Suske doesn't appear at all. Only Wiske and her aunt Tante Sidonia are present. Wiske actually had an older brother, Rikki, who was Put on a Bus from the second album on and ignored for more than 60 years in the stories' continuity.
Suske and Wiske were actually toddlers in the first stories, instead of the early teenagers they became later.
Tante Sidonia actually looked more feminine in the first stories, dressing like an old woman of her age would.
Lambik was obnoxiously stupid in the first stories and completely untrustworthy to his friends. His intelligence improved over the course of the series, though he remained not very bright.
Jerom actually dressed as a caveman for most of the first stories he appeared in. Only gradually he lost these roots and became more civilized.
Professor Barabas was originally a stutterer with a pot belly. He lost both traits later.
Also, many readers will notice that even after main characters were introduced in the series there were still stories where either Lambik or Tante Sidonia are noticably absent. Even without giving an explanation about their whereabouts!
Nero was originally a man who thought he was Emperor Nero, but was actually called "Heiremans". After a while other characters started naming him "Nero" anyway. Also, he was completely bald and only got his famous hairs in the album "De Man Met Het Gouden Hoofd", as a result of drinking from an enchanted river. Also, for the first five years of the series, the comic strip centered around Detective Van Zwam, who was eventually reduced to a secondary character while Nero became the star of the series.
In his first albums Adhemar dresses like a baby and acts very obnoxious and egotistically to get his will. This is in sharp contrast with later albums in which he behaves more civilized.
Petoetje walks around dressed like a tribal native, wearing nothing more than a tribal dress. Of course, he came from Papua New Guinea: but it takes several albums until he finally starts wearing more Western clothing!
Urbanus: He was much taller and thinner in the first albums, looking more like a young adult than the short fat Man Child in later stories. Nabuko Donosor would only become his dog from the second album on.
De Kiekeboes: The early albums look nothing like the series today. Kiekeboe is long and thin, Charlotte is a Damsel in Distress and most of the comedy is more like a typical children's comic strip of that time, with a lot of unneccessary exposition and not so clever puns as in later stories.
Tom Poes: Tom Poes was a lot taller in the early stories and looked more like a real cat than in later albums.
Superlópez began as a direct and shameless parody of Superman, mocking several Marvel Comics characters and plotlines. When the original writer Efepé left, it changed into a "regular dude thrown into a superhero role", focusing notably on López's life and work. From the 90's on, though, a decent rooster of villains had been added and the stories became more adventure-oriented, with several political jokes and references thrown everywhere.
Judge Dredd was originally set in New York City, the judges were "elected by the people" and regular police still appeared.
In the second issue of Marvel's Star Wars, the scene between Han Solo and Jabba the Hutt (or Hut here) is included, but Jabba looks absolutely nothing like the familiar character as seen in Return of the Jedi.
Though this persists for much of the comic series, as another story about Han and Jabba uses the same humanoid design as the adaptation of A New Hope. It isn't until Return of the Jedi came out that Jabba was depicted as he is now.
Jabba's humanoid design was from a scene that was originally deleted, and it was said that it wasn't the final version. At the time, they couldn't do what they wanted to, so it ended up deleted. When the "Special Edition" version of A New Hope came out, the Jabba from Return was inserted in as a CGI model.
In early issues of Marvel's Micronauts series, Commander Arcturus Rann seemed to be a less refined individual. He used slang, mild swear words, and occasionally uttered sexist comments toward Marionette. In this, he was much like Han Solo from Star Wars. This was toned down immediately after the first three issues, and he started acting like a straight-laced hero.
In his first few stories, Thor wasn't treated as the actual Thor from the myths. While Donald Blake did physically transform into Thor, the mind was still Blake's. For example, when he first meets Loki, Thor/Blake thinks about the things he knows from the myths, and not of the things he, being Loki's brother, should know.
Josie and the Pussycats started out under the name She's Josie. Josie's hairstyle was a bouffant rather than a Bob Haircut, and she had an Alliterative Name (her surname "McCoy" was originally "Jones"). Instead of Valerie, they had a friend named Pepper, who was a Deadpan Snarker and a Soapbox Sadie. Instead of Alan, we have Albert, who was also a folk singer (though it wasn't a trait of his until the seventh issue). Albert was later phased out for Clyde Didit, a guitarist whose Running Gag was being hit by something he was singing about. When Alan finally made his debut, he had his own band called "Alan & the Jesters", but that didn't last beyond that particular issue. Alexandra was lacking her Skunk Stripe, did not have witchcraft or her cat Sebastian, and was much less of a hothead initially. And of course, the Pussycat band itself did not exist until issue 45.
The Transformers established in its first issue that the titular robots evolved from "naturally-occurring gears and pulleys" on Cybertron. This origin was never mentioned again, and eventually superseded by the "children of Primus" origin established by Simon Furman.
Initially, much like previous Marvel Comics toy tie-ins ROM Space Knight and Micronauts, The Transformers was set in the Marvel Universe proper, with Spider-Man guest-starring in issue 3 (along with cameos by Nick Fury and Dum-Dum Dugan, and a thinly-veiled reference to another Marvel-licensced character, Godzillanote Marvel no longer had the license by then so he wasn't referred to by name), and the Dinobots fighting Shockwave in the Savage Land in issue 4. But after having Circuit Breaker cameo in Secret Wars II (for rights issues) and sending Ratchet to the Savage Land to fish the Dinobots out of a tar pit in issue 8, the Transformers' connection to Earth-616 was dropped.
The first issue also mention in passing that the Transformers developed their transformation abilities over the war. Practically every other bit of TF media depicts transformation as a natural ability.
More related to later media, but some TF fans reading the original run might be shocked with how little Megatron actually leads the Decepticons. After Shockwave enters the plot at the end of issue 4, Megatron is ousted from leadership and, when he returns, it's a in a dual leadership with Shockwave that ends in Megatron seemingly committing suicide. The Decepticons actually cycle through about six leaders over the series run, even more in the UK comics.
The designs in the first two issues were heavily modelled on the toys. Starting with the third issue, the comic always used the cartoon designs.
In his first few appearances Rung has a slightly different, more boxy design, which clashes with important character traits and backstory established later, like him never changing body. He also is drawn with wheels and other seemingly vehicular kibble even though he's supposed to transform into a vague, key-like object without wheels. Later issues retconned those parts to be a scooter he carries with him in order to avoid continuity/logic issues.
In the first two or three issues, Swerve comes across as being disliked by the rest of crew, with his jokes and Motor Mouth tendencies being seen as annoying. This doesn't jibe with the ideas his character arc is built around, namely that he suffers self esteem issues because he thinks people only like him for his jokes.
When first introduced in season 1, the Galactic Council is talked about as if they're the only major interstellar government around, with no mentions of the Black Block Consortia.
Comics written before Roberts came along showed Spinister as a fairly normal Decepticon soldier who served alongside elites like the Predacons and was living on Cybertron after the war ended. MTMTE explicitly establishes Spinister as the exact opposite; a stupid/borderline mentally disabled guy who would probably never get the chance to serve under someone like Razorclaw and was flying around with the Scavengers in the rim worlds after the war ended.
Another example of contradicting characterization is Drift, who lacks his trademark spiritualistic and obnoxiously upbeat persona in comics not written by Roberts, being depicted as a more stoic and serious warrior.
Nova 's 1970 series didn't have Worldmind established as a core concept of the Nova Corps, although the computers of Xandar were mentioned quite a few times. Nova was more of a Flying Brick - his powers consisted of flight, super strength, and invulnerability, rather than the gravimetric abilities he is portrayed with in modern times.
X-23, in her early appearances in Uncanny X-Men, was shown as mocking Psylocke's mannerisms, something that went against her usual stoic and loner attitudes.
An early DC Comic of The Spectre had an issue with a reporter who bore a strong resemblance to a certain mild-mannered reporter from the comics. This is lampshaded when a detective on the case orders a patrolman to "keep an eye on Clark Kent here, keep him from getting into trouble." The policeman looks at the reporter with something of awe, saying, "Are you really Superman?" This may have been a reference to one of the writers being Jerry Siegel, co-creator of Superman.