I didn't think it could be done, but Joss Whedon pulled it off.

Rating: 9/10 (4 May 2012)

Last year, I had similar reactions to both Thor and Captain America: The First Avenger. While they were mildly amusing, they were often quite boring, lacking any big-blockbuster spectacle, and seemed only around to lead into another film. That film of course, was The Avengers, and not only did I not appreciate a film out to only promote another movie, but I had little faith four films with such different styles and backgrounds would come together to work as one film.
However, the film that Joss Whedon has made completely proved me wrong and exceeded my expectations. The Avengers may actually be the best Marvel-adaption to be in the vein of the comics. It's enormously entertaining, with witty humor, and a satisfying, engaging character driven plot.
What makes the film work so well is that the filmmakers (of both The Avengers and the previous films in the Marvel Cinematic Universe) find a way to blend the characters separate mythologies into one arc that feels natural. In that sense, I have a newfound respect for Thor and Captain America, for how they properly develop their characters individually and establish their own timeline, while at the same time developing the background for some of the major plot devices in The Avengers. While Thor, and Captain America may not work as great entertainment on their own terms, when looked at as one huge overlapping arc – which also includes Iron Man, Iron Man 2, and The Incredible Hulk -, they make for a great series.
Where it seems today the only way a superhero film can be great is if it's re-envisioned to be more realistic and dark in the vein of The Dark Knight or Sam Raimi's Spider Man series, Marvel's The Avengers shows that a great superhero film only needs to satisfy it's audience, with two solid hours of action-packed, energized entertainment.