That sort of cheesiness is one of the things I've liked best about Marvel Studios films. They really embrace themselves as comic book movies. Too many movies based on comics try to take themselves seriously and while this can work will (Nolan's Batman movies) it tends to work disastrously (Ang Lee's Hulk, Daredevil). They're working with premises that are rather absurd to begin with, but the filmmakers and the audiences tend to have a lot of fun with them. The Avengers should really be a culmination of this.