"The Underworld" is a poor vampire versus werewolf movie where a vampire warrior (Kate Beckinsale) teams with a human (Scott Speedman) who wants to end the war between vampires and werewolves which has been around for centuries.
The only good thing about this movie is the dark style it is presented in. The sets and wardrobes are all dark colors, there is nothing bright and cheery in any part of the movie.
The acting is, at best, fair. You really do not cheer or boo anybody in this movie. Except for maybe the fight near the end between the lead vampire and the human, who turns out to be a hybrid of a vampire-werewolf union.
There is little to no action in this movie. Of what there is, it is nothing too exciting. The amount of blood is also pretty disappointing. Since the plot involves vampires, there should have been more blood than there is.
You also get a feel that this movie steals from "The Matrix" movies -- right down to the clothing and the "agility" of the characters. "The Matrix" movies are slightly better than this movie.
Another problem with this movie is there are numerous plot holes. One perfect example of this is the relationship between Speedman and Beckinsale's characters. The movie doesn't explore their relationship. You see them kiss once, but there is nothing to expand the budding romance.
The end hints of a sequel, but I seriously doubt there will be one. I suggest you pass over this one if you see it at your local rental store.