The massive commercial success of the Marvel Cinematic Universe is undeniable. Each movie premiere brings fans out in droves, and four of the ten highest-grossing films of all time belong to the MCU. With the introduction of Marvel shows on Disney+, the franchise has branched out into the world of streaming television, allowing for further innovation in both style and formula.

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However, from unsatisfying plot twists to lackluster character development, several projects within the MCU have been disappointing for critics and fans alike. Rotten Tomatoes' critics' rating system, the Tomatometer, illustrates which projects in the franchise have fared the worst in their critical reception.

10 Iron Man 3 Disappointed Fans And Critics Alike (79%)

Guy Pearce as Aldrich Killian in Iron Man 3

The third and final installment in Robert Downey Jr.'s Iron Man trilogy remains immensely controversial among both MCU fans and critics. Critics believed that the film lacked a sense of depth in its characters and plot, and Marvel fans heavily criticized the plot twist that squandered the Mandarin's MCU debut.

Iron Man 3 does have its strengths, however, as reviews continued to appreciate Robert Downey Jr.'s charismatic performance in the titular role. Critics did praise the poignant portrayal of panic attacks and post-traumatic stress disorder in Tony's storyline, but it wasn't enough to win over critics.

9 Captain America: The First Avenger Is A Forgettable Introduction To A Beloved Hero (79%)

Captain America looks to the right with an American flag in the background in the movie poster for Captain America: The First Avenger

Chris Evans' portrayal of Steve Rogers is one of the most popular characters in the entire MCU, but his debut film falls flat in comparison to other projects in the franchise. Despite a lackluster start, the second and third installments of the Captain America film series are beloved by both fans and critics.

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This improvement can largely be attributed to the onboarding of the Russo brothers as directors for both films. The duo would go on to direct Avengers: Infinity War and Avengers: Endgame following their work on the Captain America movies. Unfortunately, The First Avenger's reviews called the film mindless and clichéd.

8 Thor Struggled To Find Its Footing (77%)

Thor-2011-Poster

The MCU debut of Thor Odinson was largely underwhelming for both fans and critics. Directed by Kenneth Branagh, Thor sees the titular hero cast out of Asgard by his father, Odin. Without his powers, the God of Thunder has to prove himself worthy. The film's focus on Earth as a setting was criticized in reviews, as some believed that it took away from the source material's most interesting elements.

Thor certainly proves that Chris Hemsworth and Tom Hiddleston were the right choices for their respective roles. Hiddleston, in particular, would go on to become an iconic villain for the entire franchise after taking center stage in 2012's The Avengers.

7 Avengers: Age Of Ultron Has Not Aged Well (76%)

The Avengers charge In Avengers: Age Of Ultron

Fans are always excited to see the Avengers team up, but Avengers: Age of Ultron is undoubtedly the weakest film to unite the team. Reviewers criticized the sequel's uneven tone and lack of cohesion, especially in comparison to its well-reviewed predecessor.

When watched today, Avengers: Age of Ultron does not hold up well. Tony's offensive prima nocta joke, and Natasha and Bruce's uncomfortable romance are tough for even the most dedicated MCU fans to get through. Nevertheless, the film did provide an excellent introduction to Wanda Maximoff, who has since become a fan-favorite character.

6 Doctor Strange In The Multiverse Of Madness Suffers From A Disjointed Narrative (74%)

Doctor Strange in the Multiverse of Madness

Doctor Strange in the Multiverse of Madness was one of the most highly-anticipated entries in Phase 4 of the MCU. With Spider-Man director Sam Raimi at the helm, fans and critics were excited to see something fresh in the franchise. Unfortunately, the film fell short with a disjointed plot, which some audiences felt undermined Wanda's character development from WandaVision.

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Multiverse of Madness still boasted impressive acting performances, particularly from Elizabeth Olsen in a wonderful deviation from her previous appearances. Raimi's unique directorial style also shone the film, as it allowed Multiverse of Madness to really dive into horror elements.

5 Iron Man 2 Fails To Meet High Expectations (72%)

Iron Man 2 poster with Iron Man and War Machine

The MCU's first-ever sequel, Iron Man 2, had a lot to live up to. Unfortunately, the film wasn't quite able to meet these high expectations from fans and critics. Reviews consistently noted the sequel's inability to match its predecessor's quality, but they continued to praise the performance of Robert Downey Jr. in the lead role.

The 2010 film was particularly criticized for its disorganized plot that lacked innovation. Despite the criticisms, the sequels played an important role in expanding the MCU with the introduction of Natasha Romanoff and the expansion of Nick Fury's role in the franchise.

4 The Incredible Hulk Was An Early Misstep For The MCU (67%)

Bruce Banner smiles with green eyes in The Incredible Hulk

The Incredible Hulk is a regularly forgotten part of the MCU's early days. Edward Norton took on the titular role, but Mark Ruffalo replaced him before 2012's The Avengers.

Critics praised The Incredible Hulk's action but expressed disappointment in the narrative's depth. Given the previous Hulk-centered films, the 2008 film struggled to stand on its own as a worthy iteration of the character. Although Ruffalo has yet to receive a solo film as Hulk, the hero remains a staple member of the MCU's Avengers lineup.

3 Thor: Love And Thunder Is Overrun By Forced Comedy (66%)

Thor: Love and Thunder MCU poster

The fourth solo film for the God of Thunder marked the return of Natalie Portman as Jane Foster and the debut of Christian Bale in the MCU as Gorr the God Butcher. Though Love and Thunder continued to boast Taika Waititi's trademark style that made Thor: Ragnarok such a hit, many criticized it for its overabundance of comedy.

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Bale's Gorr is one of the darkest villains seen in the MCU, and this clashed significantly with the movie's repetitive comedy. Critics expressed frustration at the film's lack of depth and character development, despite the strength of the actors involved.

2 Thor: The Dark World Is Considered The MCU's Most Boring Project (66%)

Thor the Dark World movie cover with Chris Hemsworth and Natalie Portman

Like its predecessor, Thor: The Dark World struggled in its attempt to bring Thor to the screen in a strong solo film. Despite impressive performances from Chris Hemsworth and Tom Hiddleston, the film falls flat with a dull plot and forgettable villain.

The backlash the sequel suffered was a major reason behind Natalie Portman's exit from the franchise. Even prior to making The Dark World, Portman was frustrated by the departure of director Patty Jenkins. The actor was ultimately won over by director Taika Waititi and reprised her role in 2022's Thor: Love and Thunder.

1 Eternals Is The First Rotten MCU Project (47%)

Eternals movie poster featuring Sersi, Ikaris, Ajak, and more

With Academy Award-winning director Chloé Zhao at the helm and a star-studded ensemble of actors, Eternals seemed like a sure-fire hit when it was first announced. Unfortunately, the final product was disappointing for both fans and critics, and the film is the first and only MCU project to receive a "rotten" score on Rotten Tomatoes.

Eternals suffered under the weight of introducing ten new heroes to audiences on top of a premise that didn't cohere well with the rest of the MCU. The massive film's massive scale was hard for viewers to get on board with, and it's still hard to understand why The Eternals didn't get involved in the MCU's previous major events.

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