Continuity mistake: During Santanico Pandemonium's routine, two dancers take the snake away so she can step forward. As they take the snake off, the second dancer is holding only a couple feet of the snake's tail, but in the next shot, the second dancer is holding the entire snake.
Continuity mistake: In the shot where we see the bar (for the very first time) they are going to, you can see the background is flat, kind of like the building is on a flat area of land with nothing behind it. At the end of the film we see not only a giant ditch but also the trucks from over the years piled up behind the bar.
Continuity mistake: After Seth and Richie capture the Fullers, Seth sends Richie outside to start the car. Richie picks up the keys, stands up facing Kate, then exits past her to the right. As the door closes, she is standing against the wall - he would have walked to the left to pass her.
Plot hole: When Seth's piledriver gives out during the climactic fight, there are many vampires in the background politely keeping their distance while he tries to restart it. Similarly, they ignore him while both his hands are occupied with Sex Machine's whip, even though vampires are running around behind him to no apparent goal.