Overall, I thought the movie was fantastic, and I would happily see it again. However, there were a number of things that killed it for me, at times.
Prime example is anything to do with the actual history of the time period. Once the story shifted to the events of the Cuban Missile Crisis, it was like being splashed with ice cold water and being forced to wake up from a pleasant dream. Up to that point, I was fully engrossed in the film and loving every second of it. But once the mutants start taking part in the Cuban insanity, I lost my connection to the movie. Maybe it is because I'm such a history nerd, but everything from that point on just screamed 'Comic Book Movie'. And it wasn't just the absurd historical revisionism (seriously, was it even necessary for them to have set it during the crisis? Why not make up your own crisis? You're already giving people superpowers for crying out loud!), it was the fact that the ensemble cast begins to fray at the edges.
Up to this point, First Class miraculously gives each and every character enough screen time to engender interest and character depth. But once the final fight begins, we are presented with dizzying battles that, while occasionally badass, simply call attention to how many characters exist and how difficult it is to give them a satisfying conclusion. Powers are zipping about like mad. People are flying around and throwing crap at each other. It was reminiscent of the absurd battles of Thor, so over the top that it made me think of smashing action figures together from when I was a kid.
The fact of the matter is that, to give a movie fight resonance, it has to be personal. This is what makes the brief fight between Magneto and Shaw intense, as was the conflict between Xavier and Magneto; it is also what made every prior fight in the film engrossing. People have to be emotionally involved in some way or another for it to be epic. Having the fights on a small scale helps with this. Unfortunately, the end fight simply involved a lot of mutants who had never really met each other duking it on the beach, a mere sideshow to the act of trying to stop Shaw from... Wait, what the hell was he doing? Suckling on a nuclear reactor for power to do... what? Blow up the world? It was weird.
Anyways, from that point, I lost track of many of the characters and lost interest in them. In the end, they become subservient to the Xavier vs Magneto clash, wherein anyone who ever showed a bit of independence went with Magneto and everyone else went with Xavier. Unfortunately, even that inevitable confrontation felt a bit silly. It was a little bit hard to believe that Magneto was going to embrace the philosophy of Sebastian Shaw, the man he'd been trying to kill for years. It didn't make any sense that Magneto was going to take out his rage on humans because of Shaw; I found this bizarre because Shaw is a mutant. If anything, Magneto should have been able to understand from this that there is nothing that makes mutants inherently better or worse than humans. They can be just as bad and just as good. But nah. That would make too much sense.
But this is why I prefer X2. Even though X2 was about a whole lot more than Magneto and Professor X's differences, it still manages to do absolute justice to the conflict between them through the events that occurred throughout the movie while still doing immense credit to an ensemble cast of mutants and their own respective character developments. I think a big part of that has to do with scale and personal involvement of characters. I don't want to go into too much detail here (I can always watch X2 and review it later), but I think X2 superior because of the impressive balance it manages to keep in being thought provoking, action-packed, and able to develop characters excellently, even minor ones, despite a large cast. I feel like First Class would have surpassed this if only it had handled its own conclusion better. But maybe I'm an insane nitpicker. Who knows?
All in all, I loved First Class, though the climactic end felt a tad cheapened by silly historical interference and gratuitously over-the-top comic book antics. As we've discovered through the success of The Dark Knight, comic book movies that keep us attached to a relative realism are the ones that stand out. But I'll stop harping about that.
Despite my criticisms, I would easily put First Class near the top of my list of favorite comic book movies ever. The acting, particularly of Professor X and Magneto, was enthralling. The villain, Sebastian Shaw (oh, Kevin Bacon...), was pretty awesome and intimidating. The action, for the most part, was epic comic book awesomeness. I definitely hope that they'll make a sequel for this soon. A sequel might give me the development I wanted for the other characters as well as a more refined approach to the theme they seemed to want to follow (Professor X's philosophy versus Magneto's). Okay, I need to stop myself. The movie was great! I'll leave it at that.