The movie had some serious continuity issues:
1.) If Mystique's genes prohibit her from aging normally, then how is it that she seemingly matured at the same rate as a Charles Xavier, from a child to an adult.
2.) We learn that Xavier lost his ability to walk at this point of his life, but he was walking pretty damn well as an older Professor X, in a flashback scene played by Patrick Stewart.
3.) In that same scene, he was walking alongside Magneto, suggesting that they were not yet enemies until much later down the road, but this film is indicating that they first parted ways in the 60s while they were young men.
4.) Havok is supposed to be the brother of Cyclops - in the comics as well as in this movie considering his last name - but how is that possible if he'll be in his 60s by the time a Cyclops, in his 30s at the present time, enrolls in Xavier's school?
The supporting mutants were lousy, specifically Darwin, who was the first Mutant causality and, coincidentally, also the only Black member of the team. Refreshing to see racist overtones in 21st century film-making all but extinguished. That red Nightcrawler was a cop out to appease the Nightcrawler fans, obviously. The White Queen was dreadful. She looked like an old hag they plucked from one of Naughty America's "Best Friend's Mom" videos. She wasn't attractive in the slightest -- the actual Emma Frost had a body and was more striking.
Bunch of other shit, but all in all, a decent movie.