Whedon knows his way around a fanboy cult phenomenon, having created a couple with "Buffy the Vampire Slayer" and "Firefly"/"Serenity," so he's careful not to mess with what works.
Whedon (who shares a story credit with Zak Penn) spends the movie's first hour reintroducing our heroes, neatly emulating the movies in which we met them: The scenes with industrialist Tony Stark (Robert Downey Jr.) have the cagey humor of Jon Favreau's "Iron Man" movies; Mark Ruffalo's debut as Dr. Bruce Banner carries the melancholy of Louis Leterrier's "The Incredible Hulk"; Chris Hemsworth's late entrance as Thor has the same grandeur as Kenneth Branagh's movie; and Chris Evans carries over the true-blue earnestness of Capt. Steve Rogers in Joe Johnston's rousing "Captain America: The First Avenger."
In this first hour, we also meet the other two main heroes combat-tough Natasha Romanoff (Scarlett Johansson), nicknamed Black Widow; and master archer Clint Barton (Jeremy Renner), aka Hawkeye, both agents of the super-spy unit S.H.I.E.L.D., commanded by Fury (Samuel L. Jackson) and his right-hand agent, Maria Hill ("How I Met Your Mother's" Cobie Smulders). (If you're new to the Marvel universe, don't worry everything is explained economically so you can jump right in.)
But it's not all exposition, as S.H.I.E.L.D.'s HQ is infiltrated by Loki (Tom Hiddleston), Thor's vengeful stepbrother. Loki is after the Tesseract, a mysterious energy source on which Fury and his science team led by Dr. Eric Selvig (Stellan Skarsgård, introduced in "Thor") are experimenting. Loki has made a deal with some nasty aliens, the Chitauri, and wants the Tesseract to open a portal to the Chitauri's dimension to begin the invasion.
As Fury brings together the Avengers, they don't start off in harmony. Stark is too self-absorbed, Rogers is feeling lost, Thor's arrogant (hey, he's a god) and Banner is just trying to keep "the other guy" (as he calls his big green alter ego) under control. Loki is quite adept at playing on those weaknesses in his pursuit of the Tesseract.
Whedon pulls the best out of all his main players Evans' aw-shucks modesty, Ruffalo's brooding intensity, Hemsworth's studly grandiosity, Johansson's sultry seriousness, Renner's coiled energy, Jackson's coolest-guy-in-the-room confidence and especially Downey's laserlike sarcasm.
In one of his neatest tricks, Whedon throws a nod to the geeks by turning S.H.I.E.L.D. agent Phil Coulson (the great Clark Gregg) into a nerdy fanboy who has all of Captain America's trading cards but, because this is Whedon's universe, even the geek gets to be a hero.
The action is smartly paced, with Whedon pairing up his heroes fighting against and alongside each other. (Thor and Hulk are a good duo, as are Cap and Iron Man.) And there are some bravura touches, like the great circling shot of all six heroes facing the giant menace attacking Manhattan followed by an indescribably cool tracking shot that bounces from one hero to the next in midbattle.
Whedon shows there's nothing like $200 million and a lot of intelligence to entertain the holy heck out of an audience. "The Avengers' " fun and inventiveness kicks off what's likely to be a great moviegoing summer, no matter what else is released.
'Earth's Mightiest Heroes' join forces in the megasuperhero movie of the summer.
Where • Theaters everywhere.
When • Opens Friday, May 4.
Rating • PG-13 for intense sequences of sci-fi violence and action throughout, and a mild drug reference.
Running time • 142 minutes.