There are two distinct audiences for superhero comic book movies like The Avengers (Joss Whedon, 2012) and this one, its sequel. One audience is just the casual fan of action movies. The other is the hardcore devotees of the comic books on which the movies are based. Pleasing one audience without losing the other is a hard trick to pull off. The hardcore audience knows the backstories of all the characters and is likely to be turned off by any inconsistencies with the source material. But the audience ignorant of the backstories needs some exposition to get them clued in to who these people are and what they're up to. Whedon is probably the person best qualified to deal with the problem, for one thing because he brings his own hardcore devotees along with him: the fans of Buffy the Vampire Slayer, who trust Whedon to keep them entertained no matter how complicated and absurd the storyline becomes. I don't happen to be steeped in Marvel Comics lore myself, but I've watched every episode of Buffy at least once, so I appreciate Whedon's ability to take me along for an amusing ride. He does this by not taking anything in the Avengers movies terribly seriously. As in Buffy, what you have is a bunch of characters wisecracking through the apocalypse. And fortunately, the producers have enough money to spend not only on special effects but also on a huge cast of likable actors who relish the gags Whedon gives them and have the skill to play it all with the right blend of seriousness and tongue-in-cheek. In the end, the movie seems a little overloaded with stars -- in addition to Robert Downey Jr., Chris Hemsworth, Mark Ruffalo, Chris Evans, Scarlett Johansson, and Jeremy Renner, there are cameos by Idris Elba, Samuel L. Jackson, and Don Cheadle, as well as the luxury casting of James Spader as the voice of Ultron. Keeping all of them busy squeezes the action sequences into incoherence. That may be why Whedon confessed to feeling exhausted afterward and declined to write and direct the third film scheduled in the series.