If you haven't seen the trailer for The Avengers yet, here you go:
All set? OK, let's talk about what it says about the film. Joss Whedon's name is on this one, and there's something he does better than, I think, anyone else in Hollywood right now: he uses other people's material. Buffy drew on vampire movies and it didn't apologize for them or "reboot" them. It had one thing to say: what if the cute blonde in the alley kicked the monster's ass? Beyond that, it just rolled with the genre. When he did Firefly, he didn't constantly rub your face in the fact that it was a planet-of-the-week show, a concept pioneered by Lost In Space and Star Trek, but that's exactly what it was. He didn't need to tear apart the Star Trek idea and tell you he was doing so; it was its own show, and proudly part of its genre(s).
So, what does that bring to The Avengers? I think the primary thing it brings is a respect for the existing films. Tony Stark's (Iron Man) snarkiness comes through loud and clear in this trailer, making it clear that the humor of the first Iron Man movie (and to a lesser extent, the second one) inform his story in this film. It's not going to be a case of "re-imagining" Iron Man and making him Joss Whedon's Iron Man, and that's really important. Whedon's voice will come through loud and clear without having to beat us over the head with it, so he can use what the other films gave him.
On the down side, we get only a taste of Loki, but he does have that Master/Evil Spike (Buffy: The Vampire Slayer) sort of feel to him. The overwrought arch villain, which is something Whedon does well but his best villains have always been the very slightly sympathetic sociopaths like Saffron (of the Our Mrs. Reynolds and Trash episodes of Firefly), The Operative (from the Serenity film) and of course, lovable Alan Tudyk as the deeply disturbed killer, Alpha in Dollhouse. These maladjusted but brilliantly competent characters who could easily have been the hero, but for some wrong turn in their pasts, are what I look forward to in any Whedon work. Indeed, we even get to see the creation of one such villain in what I think is Whedon's best work to date: the farcical, musical short film, Dr. Horrible's Sing Along Blog. So, it's with some disappointment that I note that so far The Avengers lacks that sort of villain.
A few other observations: others have pointed to all of the civilian eyes pointed at the sky in this trailer. I won't divulge the currently hot rumor as to why that is, but suffice to say that there may be quite a lot of plot that you don't get wind of, here. Also, I'm not yet sure what they'll be doing with Black Widow or Hawkeye, but my guess is that they're going to be the cynical military types at first who our super-powered heroes need to win over in order to create a real team. That can feel tried and worn or it can build a sense of larger purpose. We shall see...
And when talking about S.H.I.E.L.D. agents, we can't skip over Nick Fury, played by Samuel L. Jackson. With his shaved head and long, black leather jacket I can't help but be reminded of Fishburne in The Matrix. Especially as he's coming out of the helicopter with his extra-large collar. The facial hair and the eye patch are the only things that make him not a caricature of Morpheus. Still, Jackson was a brilliant choice, and leather coat or no, he's entirely capable of playing Nick Fury to the fullest.
The trailer is clearly about the Iron Man character, and I expect you'll see a new trailer every month or two, now, that will focus on each of the others. I can't wait for the Hulk-focused trailer. His story is probably the trickiest in the movie, and can fall flat quite easily.
One last note on Downey: I'm always impressed with his comic delivery, but the "genius, billionaire, playboy, philanthropist," line is delivered with such ease and yet the sense that he's thinking about it and ticking off the boxes in his head... it makes it feel like wit and not just ego. Stark hasn't thought about the answer to that question before, and he's probably just as surprised by the answer as we are. That's comic gold, and it's what Downey delivered over and over in the first Iron Man movie. I can't wait for more.