Avengers Continues to Impress

The action sequences in this movie are going to be insanely awesome. Here are my doubts: this one movie has to deal with an ensemble cast of characters who for the most part all have had movies of their own. They each need to have equal screen time and also have to be grouped up fairly quickly in order to get into the actual plot of stopping Loki.
How is this movie going to be able to deal with the idiosyncrasies of each character while still having them function as a team and still manage not to feel rushed. I'm just going to hope the film ends up being super long in order to incorporate everything. And what the hell is with the decepticon snake thing at the end?