I've seen the movie three times now and had a chance to digest the film and the characters. Here are my thoughts:
Iron Man: There was too much Iron Man/Tony in movie, but it worked because RObert Downey Junior is so good. They made him look a bit too good against Thor and too powerful in general, though it didn't detract form the film that much. Defining moment for me was the scene with Loki in Stark Tower, followed closely by the scene on the bridge of the Helicarrier where he scolds everyone for not doing the readings. As Iron Man, my favorite moment was the little bit int he tracking shot where he shoots his repulsers off of Cap's shield.
Captain America: They could have and should have done a better job with Cap. I prefered his costume from TFA, but an update was fine. Just don't make it so tight and do a better job with the helmet next time. I also thought he could have look a bit stronger against Loki in Germany and against Hawkeye's troops ont he Helicarrier. I will admit that I am biased because Cap is my favorote character in comics. Defining moment: when he takes control of the final battle and gives out orders. All the fighting scenes in that battle were great too. As was his demeanor when he interrupted the Thor/IM battle.
Black Widow: Scarlett Johansson did a great job. I LOVED the Russia scene and the Loki scene. Both were defining moments. Using her "stingers" on the alien was the defining action scene for a comic book fan.
Hawkeye: While the begining of the movie made him look weak, they did a great job with Hawkeye. It was a good nod to his comic criminal past to have Loki take him over. But where he was awesome was the battle. The exploding arrow on Loki, the no-look shot and the grappling hook scene were fantastic. Defining moment? For me it was the no-look shot while calling out the action form the rooftop.
Thor: I loved the Thor movie and he has always been a character that I liked. I liked how he was shown to be a bit stronger than Iron Man (crushing the armor and probably about to finish him before Cap arrived) and not quite as strong as the Hulk, but able to hold his own. Defining moment was when he rained down lightning on the aliens fight Cap, Widow and Hawkeye. The bolts from the sky and then him landing were right out of the pages of a comic book.
Hulk: I saved the best for last. They didn't just hit it out of the park with him, they hit it out of the atmosphere. Whedon NAILED the Hulk and the visuals were amazing. Every moment on screen was defining, but the Loki beatdown takes the cake. Loved the Thor punch and initial "Hulk Smash" part of the battle. So good.
