Adolfo Velázquez’s review published on Letterboxd :
WOW! Just WOW! Avengers is such an spectacle. From beginning to end you are treated to the largest and greatest superhero showdown ever put out on Cinema! I'm not saying this might be the best superhero movie of all times, but it's surely among the top ones!
All the characters are given their time and it's nice to get some back story on the SHIELD ones. The only character that comes out uneven would be Hawkeye.
Technically it was edited just the right way, it's over two and a half hour long and it passes quickly. There's a lot of action, far more than all previous Marvel movies. One could say it even comes out having more than all of them together.
Finally one more thing: HULK SMASH!!!! What an amazing Banner/Hulk we get. Ruffalo gets Banner perfectly and we finally get a Hulk that is believable and not just some CGI soul-less puppet. One thing is certain, most of the fans will walk out of this one begging for another Hulk solo movie with Ruffalo on the role!