Joss Whedon tells a story, which, though typical, is masterfully developed. First, an enviable and satirical script defines the pace of the work, which remains strong throughout the film, building up tension to conclude in a powerful final act. This is achieved in part thanks to the characterization of the characters, well defined by their dialogues and the performances of the actors, which easily draw the different personalities of heroes and villains, trying to make the viewer vibrate with the clash of egos when they appear together on screen.
Special mention to Robert Downey Jr. as Tony Stark, Mark Ruffalo as Bruce Banner and Tom Hiddleston as Loki. The latter is a successful asset for the film, as the fun of seeing him interact on screen is only comparable to his great performance (amazing the scenes with Stark, Natasha and Thor) showing a complex, even tragic, villain (although occasionally terrifying) whose motivation, while simple at first glance, is more complex and interesting to an attentive viewer(pay special attention to his dialogue and facial expresions, particularly in the scenes with Thor, Agent Coulson and the ones in the final act.
I also have criticism, however, as the final conflict may not like, to a greater or lesser extent, to those who do not tolerate the special effects. However, I must say that such scenes are a delight to the eye, well developed not only in effects but also in cinematography and style (emphasis on a sublime Oner
where the camera follows the characters, artistically impressive). Also, Whedon is not content with what is called "Eye Candy", and the outcome gives us a remarkable argument structure to outline the relationships between its characters, seasoned, successfully, with irreverent dialogue and epic moments to make it more palatable.
Another negative, in my opinion is, that, although the premise wonderfully done, giving a good shape to a somewhat simplistic plot, as I said the movie does not redefine any trend that we have not seen before, despite the fact that shows such concepts much better than any other film of its kind. However, although imperfect, the film satisfies at all times, and the scale between hits and misses is enough to make of the Avengers an excellent film.