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)
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: At the end when the 3 vampires are shooting at Michael, Selene drops behind them. The blood on the left side of her head disappears and reappears a couple of times. When she's taken them out it's back again. And it gets bigger and smaller all during the time it's there. (01:48:00)
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: 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)
Continuity mistake: When Selene runs up the stairs to release Michael from the chains, the door she left wide open is almost closed when the pursuers reach it. (01:08:55)
Continuity mistake: When Selene discovers the blood on the wall in the subway chase the blood changes appearance between the shots. (00:07:55)
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: Right before the morphing shot of Michael's apartment building number, 510, we see Kraven enter and then leave the room through some double doors. As he enters, one of the doors is fully open and the other is half open. When he leaves they are both fully open.
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: 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)
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: 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 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: During the fight scene towards the end, Michael Corvin (now half lichen/half vampire) flies through the air from being hit. At this point Michael’s color is a translucent black/grey. As he flies through the air you can see that his feet are white. (02:00:35)
Continuity mistake: At the shooting range, Selene is shown firing a black USP without a compensator. It then cuts to an over the shoulder shot, and she is now firing a two-tone USP Match (which she supposedly receives from Kahn to test out a few seconds later). It then cuts to a frontal shot of her, and she is once again using the same black USP. She never stopped firing, so she couldn't have switched guns.
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)
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: Selene shot Singe in the right shoulder, but when she brings him in front of Viktor, the injury is in the left shoulder.
Continuity mistake: Whenever Raze transforms into his wolf form he takes off his jacket, but when he leads the other werewolves to assassinate the council members and to drain Amelia of her blood he all of a sudden has his jacket on. He couldn't have stored it on the train.
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.