The first half of the film is particularly gripping and dark, and holds the attention of the audience all the time. It is intense, fast and gut-wrenching, and belongs to the best thrillers. The villain seems invincible, and is about to kill all the mutants.
The second half of the film is slower and more predictable. The villain's power suddenly disappears and is easily killed by the mutants. This half makes a mistake most of the superheroes movies do.
Overall, it is still a decent movie worth watching.
View more about X2: X-Men United reviews