I've seen the film twice now in theaters and it was equally enjoyable the second time around. Every main character had a chance to shine. The relationships between each of them felt authentic. [spoilery review]Loki was a compelling villain. The short period where he was dressed as a human showed off his classy swagger, a quality that Tom Hiddleston carried throughout his performance - extremely fitting for a would-be king.
The intelligent banter between Pepper Potts and Stark was enchanting and hilarious. Banner was really likeable, especially for a recluse with anger issues. I particularly enjoyed how Banner and Stark became friends based on the nerd factor. Captain America came across incredibly well as an understated leader. He didn't make friends with anyone, but everyone followed his battle orders without question. He wasn't the strongest, smartest, or best trained, but he instinctively planned strategy for the group and they responded automatically to his command.
I understood the Black Widow/Hawkeye relationship better the second time around, which is understandable since they were the only two characters I knew nothing about beforehand. Strangely, my favorite moment with Hawkeye is when he gives tactical advice to Stark - that the alien craft "can't bank worth a damn." He's not himself for most of the movie and I wasn't really drawn to his self-loathing response to his brainwashing. Black Widow, on the other hand had some real spunk. Her interrogation scene was funny, and it was ten times more awesome when she tricked the high-and-mighty Loki into revealing his plans. For the first time since she appeared in the Iron Man movies, I look forward to seeing her again and learning more about her character.
For being a future king of an advanced society, Thor is still very brutish. He's the man with the hammer and the really big biceps. Which is why I liked it when he tried to use the hammer on Cpt. America's vibration-proof shield and his brute strength failed him. I also really liked the line when I think Stark asks Loki if he's afraid of thunder and Loki says, "I'm not particularly fond of what follows." The moment Thor swoops in and plucks Loki out of the helicopter/jet is arguably his most powerful moment in the movie. Sadly, Thor was tricked more times than I can count. I agree with Loki, "Will you ever NOT fall for that?" Somehow, I still liked him. He's still got heart and he's not dumb, he just tends to lose his objectivity when emotions are running high.
I wasn't enthralled by Nick Fury, but he was a good general for such an unconventional group. Agent Maria Hill was adequate, but something about her made me skeptical about the realistic possibility of such a skinny, beautiful woman being a sharp, strong, dyed-in-the-wool military personnel. She seemed a little over the top for someone of her stature.
Agent Phil Coulson, on the other hand, was awesome. Set up as the stereotypical nonchalant walking, talking suit, Coulson was chalk full of dry humor in every Marvel film he appeared. His starry-eyed behavior towards Captain America was adorable and hilarious. It was also extremely appropriate that such an every-day man should idolize an understated leader. Even more so when the every-day man turned into the every-day soldier and fallen hero. Or as Captain America put it, "the guy to make the sacrifice play, to lay down on a wire and let the other guy crawl over you." Although I loved this moment - it was a great way to rally the others - I can't help thinking, "Leave it to Joss to kill someone." Because, of course, the stakes aren't really life-or-death if nobody dies.