The writing and character development were surprisingly good. Particularly Iron Man (Robert Downey Jr.), Captain America (Chris Evans), The Hulk (Mark Ruffalo), and Black Widow (Scarlett Johansson). Clark Gregg as Agent Coulson gave a solid supporting performance. Thor (Chris Hemsworth) and Nick Fury (Samuel L. Jackson), weren't developed that much in this film and not given much back story, probably because the viewer is assumed to have seen the previous films, although the film is enjoyable even for a newcomer to the franchise. I thought some of the fight scenes didn't make a lot of sense, like the battle between Thor and Iron Man, and some went on far too long. Loki is one of those irritating evil villains who's impossible to kill. The flying aircraft carrier seemed unnecessary and highly vulnerable. The Hulk is supposed to be totally irrational, but seemed out of character in the final battle scene ending.