Short version: I don't know that it's the best movie about superheroes ever made, as "Spider-Man 2" "Dark Knight" and the '78 "Superman" loom pretty large in that regard. But "The Avengers" it's easily the best "Comic-Book Superhero Movie" ever made in terms of bringing the genre itself to the screen - undilluted, uncompromised and, finally, unashamed of itself.
Some other observations:
- This is The Marvel Universe, it's world(s), it's characters and it's rules translated into a live-action feature film as faithfully as possible; and by that virtue fairly or not it will immediately become the superhero movie by which all others will be judged and, in the immediate, probably found wanting. The subsequent Marvel movies are going to have to work a lot harder than they had been before (excluding "Captain America") to measure up to this, and I'd imagine that it will cause a lot hand-wringing for the producers of the too-far-along-to-rework "Man of Steel" and "Amazing Spider-Man;" and while the Nolan Batman movies are so much their own seperate thing form the rest of the genre (at this point it feels like even having the main character still BE Batman is a begrudging courtesy on the filmmaker's part) for a comparison it's hard to imagine "Dark Knight Rises" NOT being regarded as the runner-up in the innevitable punditry matchups.
- Worries about Iron Man dominating the movie? Shelve them. There's a lot of Tony Stark in the movie (he is, after all, "the funny one" and good for exposition) but in terms of the action beats and screentime Iron Man is more of a combination comic-relief/deus-ex-machina figure: He's there to deliver a quick-fix and land a punchline for the most part; with Thor as the serious one who keeps things on track, Hulk as the wildcard and Cap as the overall MVP.
- It's kind of genius that Samuel L. Jackson's role as Nick Fury mainly utilizes his gift for solemn, forboding delivery and straight-faced just-the-facts-isms, as opposed to the "angry, ever-shouting black police captain" cliche it could've easily been.
- If there's one innevitable "down-side" to just how good "Avengers" is, it's that it can easily be seen as the ultimate vindication of a "The Fanboys Were Right" outlook on such things - pretty much every risky/offbeat thing that makes the film work as well as it does, from the inter-film continuity to the source-faithful aesthetics to the hiring of Joss Whedon amounts to what comic fans have been clamoring for for decades. It's going to be very hard for any adaptation of a "geek" property to jettison an awkward genre/continuity relic or rework a costume/design-element without getting a tidal-wave of "It worked fine for The Avengers!!!" in retort. In other words, we've probably heard the death-knell of "Nolanizing" genre-properties - for good or for ill.
- Mark Ruffalo is the best Bruce Banner since Bill Bixby, and this Hulk is the best Hulk period. I like the Edward Norton one and I still think Ang Lee's oddball interpretation is criminally underrated; but this is the first time anyone has really pulled-off the idea that while being Bruce Banner is scary and sad... being The Hulk looks like fun. I do not envy the parents of small children the night after they see this movie.
- Jeremy Renner is VERY good as Hawkeye, but I still say they should've given him something more interesting to wear. He looks underdressed whenever he's with the other Avengers, and frankly even his ridiculous "classic" purple gear is no sillier than some of the "why would he even HAVE THAT!?" trick-arrows he busts out. (Warner Bros. is either going to very happy or very sad about their in-production "Green Arrow" show after seeing this.)
- Chris Evans was very, very good as a more deeply-characterized version of Golden Age Captain America; but he's phenomenal as a literal live-action translation of Silver Age "man out of time" Captain America. His one-line off-the-cuff appraisal of Thor and Loki is a perfect piece of writing from a character standpoint (though I think some folks will misinterpret it.)
- Speaking of perfect writing, the long-in-coming payoff to the lingering question of Bruce Banner's "secret" to keeping The Hulk in check is one of the best pieces of Banner dialogue ever uttered in any version of The Hulk in any medium ever.
- I know Marvel is back and forth about what to do with The Hulk after this (is that TV show still happening?) but someone needs to sign Ruffalo for at least more in-universe cameos yesterday. The instant chemistry and snappy rapport he has with Robert Downey Jr. as Stark is the best surprise of the whole production.
- One of the great benefits to bringing the "rules" of comic book storytelling into the movies is that, as it turns out, the "shortcuts" carry over, too: The film's brisk pace is aided by an almost gleeful pulling of the "A Wizard Did It" trigger; with what might otherwise have required tedious exposition often being handled in short conversations that boil down to: "Wait, plot-hole?" "Oh, handwave/phlebetonium/magic/cosmic, of course."
- Loki is a great choice for an innaugural bad guy, especially because he's still essentially the same "type" of bad guy from "Thor" - angry, crafty and more invested in manipulation and game-playing than big-scale supervillainy. This is necessary, since everybody knows that in superhero team-ups the good guys MUST be made to fight eachother in as many combinations as possible before they all fight the bad guys - otherwise how would we find out "who would win?"
- It is soooooooooooooo fucking refreshing to see a superhero movie where the characters joke around and the movie is allowed to be funny without it feeling like self-parody (the Schumacher Batmans) or obnoxious (what we've seen of the new Spidey's cringeworthy comedy-routine.) For me, the first two Raimi "Spider-Man" movies were the gold-standard for "takes itself seriously but knows when to go for the laugh" superhero narrative, but this overall surpasses them in that department.
- One thing that DOESN'T happen that I was kind-of hoping MIGHT happen: Captain America being able to lift Mjolnir. Probably for the best - might've taken a bit too long to explain to people who skipped "Thor" why that's a big deal, and as it is Cap already gets like four or five "Yeah, I'm the guy" moments.
- More than one person at Warner Bros. is taking a second look at the Joss Whedon "Wonder Woman" script they passed on a few years back right now.
- It'll be really interesting to find out, when the dust settles, just what DID happen in the conception of the alien army that shows up for the big finale. In the film they're called Chitauri (the "Ultimate" name for The Skrulls) but they don't have Chitauri/Skrull shape-shifter powers and they don't look like either creature or any other recognizable Marvel alien. Supposedly the shape-shifting was part of the leaked script that was around awhile back, and the Skrulls rumors were "fact" for awhile, so it almost feels like they went into shooting intending for these to be Skrulls and then had to switch it around later on when the legal quagmire surrounding those characters proved untenable. Either way, all the "what are they?" silence has led a lot of people to assume their identity is some kid of important secret, when in reality we learn their names offhand within the first minutes of the film.
- This is probably the closest to recognizably human (as opposed to unbelievably-sexy-alien-unfamiliar-with-emotion) a performance as has ever been coaxed from Scarlett Johanssen. That's not to say she's ever been "bad" (far from it) but she finally appears to be from this plane of existance.
- "Iron Man 2" is probably still the least of the Marvel movies, but the payoffs in this film to some of the smaller character beats and worldbuilding it got into are good enough to make that film a whole "star" better.
- Traditional Marvel mid-credits surprise? Yup, and it provides the most definitive answer possible to "how the HELL do they plan to top THAT?"