14. Iron Man 3 (2013)
First of all, it's pretty embarrassing to be ranked as the worst Marvel movie in history but Iron Man 3 is no shocker. The Mandarin is arguably the main antagonist of top tier Avenger Iron man in the comics. The villain was overhyped, poorly executed, and no longer available as its label turned into a joke. Aldrich Killian makes the claim that he's the "real Mandarin" but ends up being a mediocre character that proved his inferiority as Pepper Potts, who has no training whatsoever, destroys him. However, the film showcased Tony Stark's brilliance as a man without his suits. If Marvel's team implemented the Mandarin effectively then the organization could've competed with the stature of Hydra and that's saying a lot.
13. Thor: The Dark World (2013)
The Marvel fan base is widely split on their opinion over Thor: The Dark World and I guess you can say that 2013 was quite a controversial year for Marvel Studios. Malekith was under utilized despite his intriguing concept and history. Fans made it explicitly clear that Natalie Portman as Jane Foster and Kate Dennings as Darcy needed to GO after their performances in the first Thor film. However, the film had some beautiful moments including Queen Frigga's death celebration highlighting the color, water, and sky. The distinct highlight of the film was Marvel's beloved Loki as his performance was widely praised. All in all, Marvel needs to sort out their Thor solo films.
12. The Incredible Hulk (2008)
There's not much really to say about this movie except for the unappealing of the Hulk's overall appearance and how its just about Hulk on the run again. Mark Ruffalo's portrayal of the Hulk later on in the Marvel Cinematic Universe also degrades The Incredible Hulk as a film even more as Ruffalo is the Hulk that fans have come to love.
11. Iron Man 2 (2010)
While Iron Man 2 had high expectations as a sequel to the widely praised Iron Man film, the main takeaway from the movie was the interaction between Nick Fury and Black Widow along with their affiliation with S.H.I.E.L.D. in reference to "The Avengers Initiative." There was insufficient focus on Tony's story arc as it attempted to include events that'd impact the future of the Marvel Cinematic Universe. The lackluster of Whiplash as a villain was quite disgraceful... oh well.
10. Thor (2011)
Despite the respectable castings of Chris Hemsworth as Thor and Tom Hiddleston as Loki, Thor as a film felt all over the place and the supposed glory of Asgard was not felt. They struggled to find balance in the film and the direction they wanted to go. Since Thor is one of the main characters in Marvel comics and a vital member of the Avengers, let's all hope they finally get a Thor solo film right with Thor: Ragnarok in 2017.
9. Captain America: The First Avenger (2011)
Captain America: The First Avenger had a well executed combination between a war film and superhero themed movie as it was a memorable debut for Chris Evans as Steve Rogers / Captain America. However, the film doesn't make it higher on this list due to Red Skull's untapped potential as he is Cap's major antagonist in the comics. With his minimal screen time and alleged "death," he can no longer be utilized despite him being a respected villain.
8. Avengers: Age of Ultron (2015)
With the highly anticipated introductions of The Vision, Scarlet Witch, and Quicksilver, Avengers: Age of Ultron was a fun team-up movie with an interesting take on their antagonist. Ultron as the main villain possessed complex morals as he struggled to see the differences between the norms of "right vs wrong." However, the film did not get a higher ranking on our list due to the poor divisions of screen time as there were too many characters and needlessly killed off Quicksilver after his debut.