Continuity mistake: In the beginning when Rigel is about to jump off the balcony, some of his coat is hanging over the rail. When it cuts his coat is gone from the rail. (00:02:10)
Continuity mistake: In the first scene when Rigel is crouching, taking pictures of the werewolves, he is holding the camera in his right hand just as he is about to jump down. However, when he is jumping, the camera angle changes and it can be seen that he is no longer holding a camera in his right hand. (00:02:10)
Revealing mistake: After Selene jumps off the building at the beginning and lands, there is a very large upwards pull (that stays in place until the camera cuts away) in her cape near her head that is in fact the drop wire running under her cape to the harness on her back (although the wire has been edited out). (00:02:40)
Continuity mistake: When Selene discovers the blood on the wall in the subway chase the blood changes appearance between the shots. (00:07:55)
Audio problem: At the beginning, when Selene is hunting the Lycan though the subway tunnels, she is pressed against a wall, and she starts to look around the corner. Then suddenly a subway train passes by. Shouldn't we have been able to hear it? (00:08:10)
Continuity mistake: When Selene is chasing the Lycan in the subway and is surprised by him firing at her from behind her she turns around and gets down on her knees and fires back. When it cuts she gets down on her knees again. (00:08:25)
Continuity mistake: During the fight scene between the two Lycans, it shows a shot of Taylor (short Lycan) receiving a cut across the left side of his chest, but when it shows him in his human form it is on his right. (00:10:50)
Continuity mistake: Lucian has just walked into the werewolf fight right after the opening subway chase scene. His face is faintly lit in medium shots and completely in the shadows in closeups. (00:11:00)
Revealing mistake: As Lucien reprimands the Lycans for their pit fights, of the two Lycans who were just fighting and were naked during that fight, on the taller one the top seam of his underwear/pants is visible. (00:11:10)
Audio problem: Near the beginning of the movie, while Selene is looking at the CCTV video from outside the subway station, Kraven enters the room and talks to her. Throughout their conversation, the sound quality of his voice changes as he walks away from where the mic is located (by Selene). (00:17:35)
Continuity mistake: Selene is in Michael's apartment looking through photos, you can see the door to the apartment fully open in the background. When the phone rings, and we see Michael walking towards his apartment, the door is only partially open. (00:23:35)
Revealing mistake: When Selene is firing her guns in the floor making a circle of holes so that the floor collapse, you can see in some shots the angle of her guns are pointing all kinds of directions. Instead of making a perfect circle the holes would be spread around the floor and the bottom of the walls in the hallway. (00:25:25)
Continuity mistake: When Lucian goes flying over Selene's car, in the overhead shot we see that the road below him has large parts with visible concrete because there are no paving stones. But in the next shot, a close-up of Lucian landing on his feet, the road is fully paved with paving stones. (00:28:20)
Continuity mistake: When Selene slams on the brakes sending Lucian off the car, his arm blade disappears during his tumble, and reappears in the same shot once he stops. (00:29:05)
Other mistake: When Selene's car plunges into the Danube, her car hit the bottom of the river on it's side (the passenger's side). When the camera closes up to the window of the car, you can see water flowing in from the roof of the car (as a result from the holes created by Lucian). It should flow (or at least accumulate) towards Michael's direction because of gravity but it did not. (00:29:45)
Continuity mistake: When Erika discovers that Michael has been bitten - just before he leaps out of the window and escapes the vampires' mansion - there is a patch of blood above Michael's eye that disappears. (00:36:55)
Continuity mistake: When Selene breaks the glass and takes out the old book the amount of broken glass on the book differ between shots. (00:39:55)
Continuity mistake: When Michael grabs Adam's arm and Adam tells him to let go, Michael is holding Adam's arm close to his chest. When it cuts, Adam's arm has moved over to his shoulder. (00:42:30)
Continuity mistake: When Selene writes "VIKTOR" on the mirror you can see the writing has changed in the next shot before she wipes it off. (00:43:35)
Continuity mistake: As Viktor's tomb is opening there is a shot from above showing Selene looking down the opening tomb. Watch the placement of her feet. In the next shot, her feet have moved closer to the opening. (00:44:40)
Chosen answer: In most of the shots, Lucien takes his coat off when he changes to wolf form, and the blade would be attatched to a mechanism in him coat. Also, the film gives us an example of the blade hurting a vampire: bloodloss. And that kind of weapon could do some serious damage, and as it probably wouldn't kill the vampires, it would almost definitely slow them down.