The most egregious shortfall in this regard is Nightcrawler (Alan Cumming), who gets a couple of good action scenes before his characterisation is boiled down to that of a stereotypical religious fanatic who physically self-flagellates, like Paul Bettany's character in The Da Vinci Code.

Introducing a new band of mutants would be all well and good if we were given sufficient time to understand their motivations and see their flaws, in the way that the first film did with Wolverine and Rogue. Put simply, there's only so many people with special effects coming out of their hands that we can take before it all feel like sub-par Harry Potter. In the case of X2, we are effectively told to assume that everyone we meet will be in some way magical, with less effort being expended into not defining them around their powers or abilities. Once the opening sequence in The Fellowship of the Ring is out of the way, we have a sufficient understanding of the power and threat of the Ring to see us through, with more information being built upon this firm foundation. One of the great successes of both X-Men and Peter Jackson's trilogy is that it introduced its characters' fantastical capabilities very gradually. Sticking with The Lord of the Rings for the moment, there is the issue of the different mutants' powers. While The Two Towers incrementally brought in new characters by working hard to explain the culture in which they found themselves, X2 gives us lots of people we are supposed to care about but not enough individual conflicts to justify our attention. The film's alternative title, X-Men United, should be taken with a hefty slice of irony, since while the characters are uniting against a common goal, our attention is getting endlessly sidetracked by the new characters and sub-plots, some of which aren't given the room they need to grow.

The big mistake that Singer makes with X2 is trying to introduce too many different characters or aspects of the canon at once. But while this film does deepen the existing relationships between the characters established in the first instalment, it ultimately becomes a little too cluttered and lacking in focus to either equal or exceed it. It's completely logical that Bryan Singer would want to use X2 to expand the X-Men universe on screen with less time being needed to set up the world from the first film, there is more scope for introducing some of the more complicated elements of the X-Men mythos. In this context the success of X-Men was a pleasant surprise, with a sequel being given the go-ahead shortly after its release.

The mid- to late-1990s were a dark time for superhero films, with everything from Tank Girl and The Phantom to Batman and Robin and Steel pointing to a tired genre and an increasingly spandex-weary public. It's easy to forget that in the so-called dark ages before the Marvel Cinematic Universe existed, comic book film franchises were not always planned out in infinitesimal detail before the first instalment had a chance to break even.

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