Since Marvel Studios announced the all-star cast for The Avengers at Comic-Con 2010 — Robert Downey Jr. (Iron Man), Scarlett Johansson (Black Widow), Mark Ruffalo (The Incredible Hulk), Chris Evans (Captain America), Jeremy Renner (Hawkeye), Chris Hemsworth (Thor), and Clark Gregg (Agent Coulson) — fanboys and girls have eagerly anticipated the comic-book-hero dream team flick, which comes out next May. Now, at last, the first full-length trailer gives fans a taste of the action, including plenty of smashing, shooting, exploding, flying, and, of course, witty banter. (Watch the trailer below.) Here, five things that already have critics and fans buzzing:

1. Terrific tension exists among the superheroes
We've all seen superheros fight villains, says Anthony Breznican at Entertainment Weekly, but it's "the inter-office hostility that will elevate The Avengers above just the usual save-the-day theatrics." Captain America and Tony Stark, for instance, tussle. But it's not just "verbal jabs: We also see Cap and Chris Hemsworth's Thor brawling in the woods, with the big, blonde god from Asgard swinging his hammer down on the crouched soldier's upraised shield." Make no mistake: "This rules."

2. Great talent abounds
From the first glimpse of Mark Ruffalo as David Banner/the Incredible Hulk to "Robert Downey Jr.'s signature wisecracks," from "Scarlett Johansson in her curve-hugging Black Widow suit" to "Jeremy Renner firing arrows," the trailer highlights plenty of star power, says Jen Chaney in The Washington Post. "I'm frankly in a bit of a lather over the male cast," admits Linda Sharps at The Stir.

3. But Robert Downey Jr. is the standout
"Downey, as per usual, gets all the best lines," says Hugh Hart at Wired. For instance, he snaps at Captain America, "I don't play well with others." Poor Cap "doesn't stand a chance at out-quipping the playboy/billionaire/inventor." "Ah, Mr. Downey," says Chaney. "Will your uber-confident sarcasm ever grow old?"

4. The trailer is impressively stuffed with action
In one minute and 45 seconds, says Kara Warner at MTV News, we spotted at least 12 explosions, three "gratuitous 'suiting-up' shots," six "avengers-in-action moments," and two scenarios in which Avengers get thrown out of glass windows.

5. But frankly, it could be better
"The trailer didn't deliver everything we were hoping for — nor did it have the ineffable coolness we might have expected," say Eric Ditzian and Josh Wigler, also at MTV News. "We wanted to see the Avengers assemble — not around the boardroom table, but in action."