Comic book geeks, rejoice. As should fans of monster special effects, zippy banter and Robert Downey Jr. This earth-shaking extravaganza -- which unites six superheroes -- brings it on all fronts. It even overcomes a murky setup: Evil Loki (Tom Hiddleston) steals an energy supply in hopes of starting a war. Or something. All that matters is that his plan leads Nick Fury (Samuel L. Jackson) to recruit an A team, including Iron Man (Downey), Captain America (Chris Evans), the Hulk (Mark Ruffalo), Hawkeye (Jeremy Renner), Thor (Chris Hemsworth) and Black Widow (Scarlett Johansson).
Weaving together these caped crusaders (plus their secret identities) could have resulted in a convoluted mess, but director-cowriter Joss Whedon gives all of them souls and ensures everyone delivers at least one killer blow and one killer zinger.
Downey shines brightest as he gets to shoot into space and good-naturedly rib his cohorts (to Hulk's alter ego, Bruce Banner: "You do Pilates?"). Johansson, meanwhile, impressively dispatches goons with her hands tied behind her back.