Terrifically fun reboot of a somewhat tired franchise, that wisely focuses on the two most interesting characters of the X Men universe - Professor X and Magneto.
The introduction of Erik as a child within a Nazi camp is harrowing but electrifying, the discovery of his powers ultimately tragic. It lends to such an understanding of Magneto in the later films that was only ever hinted at, and you can completely understand his character arc and his actions. Fassbender is phenomenal as the older Erik, he is both cold and calculating yet his scenes with Charles are moving revealing some warmth (in particular the one where Charles reads his memories). He is clearly an actor destined for great things.
McAvoy makes an interesting Charles. He is light and cocky and, to be frank, a little bit cheeky. Watching him change as he becomes aware of the mutant world around him and how he can help it is more subtle but equally important to understanding the later Professor X. His relationship with Mystique is extremely interesting, and as a non-comic book reader, completely unexpected, and Lawrence is solid in the role.
Bacon as Sebastian Shaw is a delightfully evil villain, so hell bent on destruction that he disposes of everyone in his path. It's played with a slight pantomime edge but it works and is never embarrassingly laughable.
Whilst watching Charles and Erik become firm friends then become enemies is the key joy of the film, it's a shame that the additional characters are so dull and lifeless. Considering that this movie could really have picked any minor mutant it wanted, it choses to add a rag tag bunch of mostly uninteresting youngsters with no personality and powers that are largely unispiring.
Add to this the real blandness of Shaw's henchmen (including January Jones who has little to work with personality-wise) the film becomes a bit unstable with noticeable troughs of interest when the main characters aren't on screen.
Having said that, it doesn't overly detract from what is essentially a great film and an exciting preview of X Men-related things to come. The final shot of Magneto in all his helmeted and caped splendour sends a shiver down your spine that leaves you aching for more.
9/10