Continuity mistake: Near the end of the attack of the Brides, Marishka is about to make her final "charge". The wind blows the hair back from her face, showing that she is not wearing any earrings. Yet after Van Helsing kills her and she starts to disintegrate, she is wearing large triangular dangling earrings. (It's not because her jewelry disappears in her flying form - she is shown wearing bracelets and rings in *both* forms).
Continuity mistake: In the scene at the beginning of the movie where Dracula is at Dr. Frankenstein's castle, he says "over God." He then turns around with his arms at his sides and speaks to Dr. Frankenstein, with his arms remaining at his sides. When the shot changes to show Dracula's back and Dr. Frankenstein's front, we can see Dracula's fingers near his chest as if he pressed his hands together. There couldn't have been time between shots to change them from his sides to his front. (00:02:30)
Continuity mistake: At the very end, when the werewolf leans over the dead girl before picking her up, her eyes are open, but when he turns around with her and faces the camera, her eyes are closed. The werewolf could not have closed her eyes with his paws and claws nor with his arms full with the girl. (01:52:55)
Continuity mistake: As the first vampire charge and Van Helsing pulls up his weapon you see Anna bending down beside the well. It the cuts to a shot from above where the three vampires come flying against the camera. At that point you can see the well and Anna isn't standing anywhere near it. When it cuts to Anna shouting "Everybody inside." she is standing beside the well again. (00:24:50)Mortug