The Marvel Cinematic Universe is a massive juggernaut in the entertainment world, dethroning Star Wars and Harry Potter for pop culture supremacy. Over the course of twenty-three films and two TV series, the MCU has been thrilling fans, bringing Marvel's superheroes to a wider audience than they've ever known and smashing box office records. Legions of fans love the MCU, and for good reason.
The MCU often casts the illusion of being comic accurate, but beyond the costumes, there are a lot of differences. Contrary to what its ardent fans think, the MCU makes mistakes. While the movies adapt many classic stories from the comics, it often ruins those stories in a variety of ways.
Updated on September 13th, 2022 by Casey Lawrence: This list has been updated to include relevant information and additional details regarding the comic source material.
10 Infinity Gauntlet
Adapted In Avengers: Infinity War (2018)
Avengers: Infinity War is one of the most beloved MCU movies of them all and is the culmination of years of movies. It acts as an adaptation of one of Marvel's greatest event stories, Infinity Gauntlet, by Jim Starlin, George Pérez, Ron Lim, Josef Rubinstein, Tom Christopher, Bruce N Solotoff, Jack Morelli, Max Scheele and Ian Laughlin. While it's a good movie, it's a terrible adaptation.
The worse part was the change to Thanos' motivations. In the comics, Thanos was motivated by his love of Mistress Death to kill half the universe. The movies had him attempt to kill half the universe to save the other half, which was both moronic and missed the nihilism metaphor. While the movie tried to go for faux profundity, it ruined something that was actually profound.
9 "The Kree-Skrull War"
Adapted In Captain Marvel (2019)
Captain Marvel is a much better movie than it gets credit for. Unfortunately, it uses the classic Avengers story "The Kree-Skrull War," — by writer Roy Thomas; artists Sal Buscema, Neal Adams, John Buscema, Sam Grainger, Sal Buscema, George Roussos, and Tom Palmer; and letterers Sam Rosen, Mike Stevens, and Art Simek — as a background plot.
This is a massive waste of a classic story. "The Kree-Skrull War" brought the Avengers into the greater Marvel Universe, showing them facing down a cosmic war. Using it as a background in an MCU origin movie is extremely insulting to one of the greatest Avengers stories of all time.
8 "Extremis"
Adapted In Iron Man 3 (2013)
Iron Man 3 isn't among the top MCU movies, but it's still pretty good, inspecting Tony's trauma from the events of The Avengers. A lot of fans were mad about the Mandarin bait and switch but what they should've been mad about is the way it wasted "Extremis," by Warren Ellis, Adi Granov, Randy Gentile, Adi Granov, Tom Brevoort, Molly Lazer, Andy Schmidt, and Nicole Wiley.
Easily the best Iron Man story of the twenty-first century, it depicted Iron Man facing a foe who was more powerful and technologically advanced than he was. Re-imagining Iron Man as a futurist instead of just a weapon-designing industrialist, it's much better than the movie that used it as source material.
7 "Winter Soldier"
Adapted In Captain America: The Winter Soldier (2014)
Captain America: Winter Soldier is still one of the best MCU movies. It has everything: action, pathos, and significant character development. However, it can't hold a candle to writer Ed Brubaker and artists Steve Epting and Mike Perkins' "Winter Soldier" epic. The movie did a lot of great things, but there's just so much more to the comic.
Captain America: Winter Soldier used Hydra as the controller of Winter Soldier, while the story in the comic used Alexander Lukin, an ex-KGB agent. The source material also involved the Cosmic Cube, Red Skull, and more. The movie was good, but it's hard to compare to the epic original.
6 Tales To Astonish #90
Adapted In The Incredible Hulk (2008)
The Incredible Hulk is the forgotten MCU movie. It isn't a bad movie, but its troubled production history and the later replacement of Edward Norton by Mark Ruffalo make it the black sheep of the MCU. However, it also serves as an origin movie for the villain the Abomination and that's where it fails.
In Abomination's first appearance, Tales To Astonish #90 — by writer Stan Lee, Gil Kane and Sam Rosen — he's a Russian spy trying to get Banner's gamma bomb. This is better than the movie's origin, where Blonsky's just a soldier trying to stop Banner before taking a serum and becoming a monster.
5 Avengers Disassembled & House Of M
Adapted In WandaVision (2021)
WandaVision was the MCU's first TV show and an unequivocal success. There's a lot to love about the show and it takes inspiration from several Scarlet Witch-centric Avengers stories, like Avengers Disassembled (by over 30 writers and artists, including
Brian Michael Bendis, Jim Cheung, Steve Epting, David Finch, Gary Frank, Michael Gaydos, David Mack, Alex Maleev, Mike Mayhew, Steve McNiven, Mike Oeming, George Perez, and Eric Powell) and House Of M (by Brian Michael Bendis, Olivier Coipel, Tim Townsend, and Frank D'Armata).
Both stories highlighted Scarlet Witch going bad. WandaVision used these stories for inspiration, showing her using her powers in a greedy way, but it didn't go far enough with the character or her downfall. Sadly, the great show didn't do as much with Wanda as many fans hoped that it would.
4 Thor (Vol. 1) #362
Adapted In Thor: Ragnarok (2017)
Thor: Ragnarok was a great movie, but it wasted more than one great Marvel story. The first is the story that deals with the titular "Ragnarok," found in the pages of Thor (Vol. 1) #362 by Walter Simonson, Max Scheele, and John Workman. Simonson's Thor epic is one of the greatest Thor stories of all time, but the movie barely explored the content.
For fans of that classic story hoping to get a big-screen adaptation of it, the movie was disappointing, but it won the fans back by being the best Thor movie, combining action and humor in wonderful ways. Still, seeing Simonson's Ragnarok on the big screen would have been amazing.
3 "Planet Hulk"
Adapted In Thor: Ragnarok (2017)
"Planet Hulk," by Greg Pak, Carlo Pagulayan, Aaron Lopresti, Jeffrey Huet, Randy Gentile, Joe Caramagna, and Chris Sotomayor, is one of the greatest Hulk stories of all time. Sent to the planet Sakaar by members of the Illuminati, Hulk is embroiled in a massive planetary war, gaining allies in his battle, and trying to free the planet from its repressive monarchy.
Thor: Ragnarok used the story as a background for the movie and it wastes an amazing story. While Thor: Ragnarok remains a great film, it uses too many epic narratives as set dressing when they should've received their own full-length projects.
2 "Ultron Unlimited"
Adapted In Avengers: Age Of Ultron (2015)
Avengers: Age Of Ultron is the least beloved of the Avengers movies. Ultron is one of the greatest Avengers villains of them all and the movie squandered him by making him into a jokey MCU villain instead of the terrifying android. While it borrowed from many Avengers stories, a lot of it was influenced by "Ultron Unlimited."
Crafted by Kurt Busiek, George Perez, Al Vey, Tom Smith, Wes Abbott, Richard Starkings, and Comicraft, "Ultron Unlimited" was one of the best Avengers stories of the past thirty years. Sadly, the movie was subpar in comparison. Highlighting one of the Avengers' greatest battles against the genocidal android, it deserved much better.
1 Civil War
Adapted In Captain America: Civil War (2016)
Captain America: Civil War uses the events of several MCU movies to begin the titular civil war between the heroes and is based on Civil War by Mark Millar, Steve McNiven, Dexter Vines, Chris Eliopoulos, and Morry Hollowell. While it has some similarities, the movie exists as an efficient action scene generator and that's it.
The movie misses all the subtext of the comics, makes Iron Man look justified because of his popularity, and shoehorns in Zemo as the villain, which misses the point of the original story. The comic was a look at the question of security versus freedom, and the movie feels like an excuse for a cool fight between the heroes.