The origin story is crucial to all superhero epics, from the gods of ancient Greece right down to Superman’s parents. Next in importance is an explanation of superpower: what they are, how they work. That’s reasonable when there is one superhero, like Superman or the Crow, but in "X-Men, " with eight major characters and more in supporting roles, the movie gets top-heavy. At the halfway mark, it has just about finished introducing he characters. That matches my experience of the "X-Men" comic books. The characters spend an inordinate amount of time accounting for themselves. Action spills across full pages as the heroes splatt and kerruuunch each other, but the dialogue balloons are like little advertisements for themselves, as they describe their powers, limitations and motivations.