I know this is horribly late...but I just found the topic and have so many issues with the movie that I can't hold it in.
If you know nothing about the X-men Universe it is indeed a decent movie. If you know a lot about the X-men Universe and you like movies that stick with canon then it is horrid.
1. They only had one member of the canon First Class in the movie. Jean Grey, Cyclops, Beast, Iceman, and Angel were the canon characters for First Class. They were all led by Xavier, and Magneto were not allies at that point any longer (if I remember correctly). I'm not even going to get into a rage about the characters they chose for the movie.
2. The villains in the movie were from a later series of comics! The Hellfire Club, Sebastian Shaw, and Emma Frost would never have been in the time of First Class. Emma Frost didn't even come along until after Jean Grey DIED!!! There were so many other villains they could have used instead of trying to retrofit The Hellfire Club into their time frame.
3. Azazel is a lackey to NOONE! Azazel is an ancient demonic humanoid mutant that killed ANGELS! He is a highly intelligent mastermind who would laugh in the face of mere mortals like the Hellfire Club. He nearly opened a gate to hell that would have ended existence for the Marvel Universe. But no, the movie he was a mute assassin...awesome. Azazel would have been the perfect villain for the movie, considering he is Nightcrawler's father...
4. If you are going to choose characters from the Marvel Universe, even if they aren't canon, at least get their powers right. Havok doesn't do the hula to use his abilities, he used his freaking hands!!! (He is Cyclops' brother so...great fuck up movie ha.) They put Angel in the movie...but it was a female who had dragonfly wings and could shoot little balls of explosive flame...Not the male Angel who can fly with real angelic wings.
5. The movie contradicted its own freaking canon. The world is supposed to exist in the same world as the first 3 movies. They use the same actress for the older Mystique as they did in the original X-men movies, as well as the same Wolverine.
6. Xavier lost use of his legs through a battle with Lucifer, and when Lucifer dropped a stone on Xavier's legs, Xavier lost use of them. It was unnecessary to have him shot to get rid of the use of his legs, and its too ordinary. Why wouldn't you want to show a huge battle between Xavier and an alien supervillain...Fail on the movie.
7. You don't have the characters solve a huge thing that happened in actual history! The Cuban Missile Crisis was a huge thing in history, why fuck with it. There was just starting to be an issue with mutants and humans in the first X-men, why would they want to start that out earlier and make it worse.
8. There was so much material that the movie could have pulled from. But instead they follow the pattern of the original X-men movies and use the most useless and boring story lines that they can use.
And honestly, besides not following the canon, the movie had a lot of other short comings. The acting was horrid on most of the actor's parts. The only good actors were Michael Fassbender (Magneto) and Kevin Bacon (Sebastian Shaw). There was a lot of choppy dialogue and poorly written dialogue.
Nerdrage...over. (Though I may think of more later.)