On the minus side, everyone's inability to shoot straight really irked me. I mean, who trained these people? A stormtrooper? Also, there seemed to be no real world impact on this centuries-long war between Vampires and Werewolves; I was thinking as Kahn's men invaded the Lycan base: where's all this hardware coming from? How can you have a mass shoot-out in a public subway and nobody Official bats an eyelid? Everything just seemed completely divorced from 'everyday life', as though this was just a private war that didn't affect normal humans any. I mean, if you you saw some chick dressed in a tight, shiny, PVC catsuit and long PVC trench-coat would you just walk on by? In fact, the Vampires didn't seem that different from humans, except they have pointy teeth and can't go out in the day. Running water is supposed to harm Vampires, yet in UW rain doesn't affect them and Selene can survive driving her car into water. Also, I couldn't work out what the Vampires were supposed to be doing when they weren't trying to kill Lycans. What are their motivations? Just hang around looking bored and sexy? They appeared to have invented a synthetic blood stock, so they don't need to prey on humans - again another way in which the characters are 'divorced' from Real Life, it doesn't affect them and they don't affect it. Clearly there's some sort of group politics going on, mainly in the way there are two (three?) Vampire covens and the leaders (Viktor, Amelia, and Marcus) take it in turns - in accordance with the Covenant - to rule. But rule what exactly? It almost seemed like Vampires wanted power for power's sake, especially Kraven and Erika.
At least Lucian and the Lycans had decently explained motivations imo, the need to create a half-Vampire, half-Lycan hybrid that would end the blood feud - something that he had tried through conception with Victor's daughter and when that failed though finding the untainted Corvinus virus. He seemed almost pleased when he saw that Selene and Michael were falling in love as it meant his dream would (possibly) outlive him.
Watching the film I couldn't help comparing UW unfavourably with another modern updating of the Vampire legends, and for my money, the best modern-day depiction of Vampires remains the UK mini-series, 'ULTRAVIOLET'. (Check out: http://uk.imdb.com/title/tt0169501 for details.) There the Vampires had much better motivations behind their actions, which made them more believable. Also, rather than resorting to 'dodgy science' with ultraviolet 'irradiated fluid' bullets, the humans in 'Ultraviolet' used carbon bullets, an echo of the wooden stake through the heart idea - and they were better shots too. :-) One of the things that makes Ultraviolet 'cooler' than Underworld is that it kept the whole 'Vampires don't cast reflections' thing, which UW junked, and also added electronic media to the mix, so Vampires don't show up on CCTV, photographs or electronic voice transmission, such as mobile phones. It doesn't have the Matrix-ish wirework and interminable gun battles that feature in Underworld, but it does have a first-rate storyline, terrific performances from the cast, a chilling score and is well worth checking out if you ever get the chance to grab the DVD.
Underworld was good, but imo it could have been better. 6/10