This bumper pack of superheroes from Marvel will be catnip to the nerd army of comic-book fans and a just-about-tolerable two and a half hours to the unconverted.
Joss Whedon, fresh from The Cabin in the Woods, has a decent command of pace and an obvious relish for the possibilities of a pecking order among characters previously answerable to nothing but their own potency.
Now, with a global catastrophe looming, they must subsume individual will to the collective good. Trouble starts when a glowing cube called the Tesseract is appropriated by god of misrule Loki (Tom Hiddleston), who with a poke from his magic spear brainwashes a crack marksman (Jeremy Renner) and a top scientist (Stellan Skarsgård) into his evil scheme of world domination.
In response Nick Fury (Samuel L.Jackson), head of international peacekeeping, summons a few good supermen: Iron Man (Robert Downey Jr), Captain America (Chris Evans), Bruce Banner aka The Incredible Hulk (Mark Ruffalo), Loki's half-brother Thor (Chris Hemsworth) and, keeping the feminist end up, Black Widow (Scarlett Johansson).
Sorting out the backstories and getting all these guys into one room means that the first half of the film is pretty talky, though Whedon's script sparks up the exposition with some smart one-liners and comebacks, most of them courtesy of Downey Jr, the flash, flip prankster of the bunch.
It's when battle commences and the supertoys come out of the box that non-committed viewers might find their attention wandering. Immoveable objects can only encounter irresistible forces so many times before it becomes a bit routine. Hammer of Thor versus the bulk of Hulk? Who cares?
Once the faceless alien hordes descend to earth it's even harder to feel involved, or to know precisely what's at stake: the way Manhattan gets tossed about like a salad makes you wonder if any part of it will be worth saving.
Of course it's about one hundred times brighter than Transformers and Michael Bay's imbecilic spinoffs, and should keep multiplexes everywhere in its competent grip. But I didn't love it.