The culmination of Marvel's four-year, five-picture master plan is, puzzlingly, both as good as I'd hoped and a mild disappointment. It excels at playing up the larger-than-life aspects of the story, from the testy initial relationship between heroes and the looming magnitude of the threat they're called together to face. Such moments are dispersed liberally, perhaps once every five minutes, and they're an effective method of keeping the audience on the hook for the duration.

What's missing, at least from where I sit, is a measure of substance or depth behind those fireworks. Robert Downey Jr. is again excellent in his nuanced interpretation of the paradoxical Tony Stark, and Mark Ruffalo might just be the best Hulk ever to grace the silver screen, but by comparison the rest of the cast feels quite thin, shallow and (for lack of a better word) cartoonish. Captain America, for example, wears a completely different personality than he did in his solo picture, and never feels quite right as the commanding field general he's presented to be. The most intriguing aspect of his character, an emotional detachment from modern culture, is barely even mentioned. He, and the rest of the team, feels like a suit of armor with a few good one-liners, not a living, breathing human being. That's a trap that was mostly evaded in the stars' preceding solo shots, so it's a shame to see it tripped here, especially given the amount of time and effort that was expended to define each individual's motivations.

Those nitpicks certainly aren't enough to stop me from enjoying the closest thing we'll ever get to an all-splash-page crossover mega-event on the big screen, but they're also irritating enough to keep tickling the back of my mind while the next set of fuses are lit. It's a herculean effort with some truly great rewards, but not the picture-perfect ensemble masterpiece it would have you believe.