X2: X-MEN UNITED is bigger, badder, and better than the first one, but in essence, what we said the first time about special effects, attractive stars, fun action sequences, and the perfect popcorn-movie tone applies to this one, too.
That said, while this movie is all about the action, there are so many characters that it's hard to include them all in anything meaningful, giving parts of the movie the feel of a prolongued introduction. The comic fans want to see every character up on the screen, and the movie tries to make it happen. But the result is that it is hard for people who are not familiar with the stories to keep everyone straight or develop much of a commitment to any of them. Halle Berry and Anna Paquin in particular are still criminally underused. The most memorable character is Mystique, played by Rebecca Romjin-Stamos, who is so good that she can even act under all that blue paint and those sequin-like scales. Alan Cummings is a welcome addition as Nightcrawler, but his German accent and Biblical references seem out of place and attracted some laughter from the audience. This is handled with more sensitivity in the comic books, where he is portrayed as a devout Catholic.