Avengers Assemble is different, of course. (When I first saw the film's title I thought - Avengers Assemble what? An Ikea bedstead? That's pretty damn hard, but a whole film about it? Really?) The heroes already exist in the same comic book universe. Bringing them together is a fan's dream. It also stems from the childhood need to collect all your playthings into one big meta-playground. The film sees Earth under threat (again) from the usual mysteriously motivated aliens with big weapons, and an energy source called the Tesseract, a hyper-cube that can open portals into other worlds. If it falls into the wrong hands... well, you can probably guess. Oh, and Loki, Thor's brother, (a fantastic Tom Hiddleston, who really ought to be given his own film) struts around smiling a lot and looking inscrutable because that's what monstrous evil people do, isn't it?
There are three problems with Avengers Assemble. But first, let's get the good stuff out of the way. Joss Whedon manages to leaven proceedings with a bit of wit - if it was a curry it would be a lamb korma. The actors give it their best shot, too, with some particularly good lines from Chris Hemsworth as Thor, and everyone yomps and punches and fixes things (there's a lot of fixing things) with aplomb.
So. The first problem is that the threat is so vague. Oh dear, the earth's under attack, again. What is it this time? Giant scaly flying tortoises? Sigh. Things that are alien have all but ceased to be frightening: things are much more scary when they come from within.
The second is that though the film consists of one frenetic scene after another, it actually manages to drag. That's largely because of its entirely predictable arc. Yes, there is a bit of friction between the Avengers; yes, there will be a moment when everything looks like it's going to fail; but yes, of course, it doesn't. And the film itself knows this. One of the characters (with whom I think the director thinks we have a lot more sympathy than we actually do) says to Loki that he'll never win. We know this. That's partly why we're watching this film; we don't go to watch superhero movies to see the world blown up. But the film would have had more of a hook if the threat felt genuine; the villains more pressing; the tensions less contrived.
The third problem relates to the assembling (I ought to call it mustering, really) of the heroes. Though the film managed not to spend too much time on their back stories, and getting them all together, there really were too many of them to care about. And since they're all super heroes - bar Black Widow and Hawkeye, who as far as I can see are just pretty handy in a fight - it's not that interesting watching them fight. The film does a good job of adding some spark to the battles, particularly with the Hulk. Ultimately, though, one can't help but feeling that these uber-men ought to be kept apart.
A much more interesting proposition would be to see Loki having to become good. That I'd love to see - the monster redeemed. The problem with heroes like Captain America is that they're just too damn boring. It's the same as Galahad, or Jesus Christ in Paradise Regained. You need your Lancelot, just as Milton knew that Satan was more interesting to write about. So, Marvel, I ask you: give Tom Hiddleston a chance. Avengers Assemble might be a comic book fan's dream - but maybe it should have stayed that way.