If you want to see a good movie with Kate Beckinsale, this is not it. Of course, I doubt a movie about an eternal war between vampires and werewolves is going to be a mass-market success. With a no-name cast and a first time director whose only previous movie credits seem to be as assistant props for Independence Day and Stargate, it comes as no surprise that this genre film is not a masterpiece of the silver screen. Would you expect a movie where all the vampires wear revealing formal wear or various leather outfits and the werewolves, in human form, look like grunge fans to be a masterful drama? Of course not, and unsurprisingly, the movie has many weaknesses: the plot is confusing and illogical at best, yet mostly just nonexistent; the dialogue is horrible; and the forbidden romance between Selene (Kate Beckinsale) and Michael (Scott Speedman) has to be one of the coldest in movie history. In fact, I think Michael has no more than ten lines in the entire movie, and he's the main male character. Something's wrong when one of the main characters doesn't say anything.
Of course, this is an action movie, so things like dialogue and plot aren't supposed to matter. What matters are things like special effects, gun battles, and the like. Here Underworld is a lot of fun, with some wild gun battles, cool cars, sexy vampires, and hulking werewolves. Most of the action revolves around gun battles, with the werewolves' UV-light bullets (don't ask me how they work, they just do) and the vampires' silver nitrate bullets thrown into the mix for gory immortal deaths. If you stay long enough (unlike the large amount of people that left in the middle of the movie when I saw it), you get to see werewolves in full lupine form running down the sewers after vampires and a particularly gruesome, yet hilarious decapitation.
Despite Underworld's many shortcomings, I enjoyed it for the entertaining fights and laughable plot. The movie may take itself too seriously, but there's no reason you have to. If you go expecting a good movie, you'll be sorely disappointed, but if you go for a few laughs, I'm sure you'll get your money's worth.