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.
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.
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.
Visible crew/equipment: During the scene where the Geckos first enter the Titty Twister, right after the shot where Seth takes the bottle of whiskey and glasses from the bar the camera cuts between shots of the bar, right after the band finishes the song a camera is visible in the lower right corner.
Continuity mistake: Right after Salma's dance, Chet, the bartender and another big guy walk up to Seth and Richie and accuse them of kicking him and breaking Chet's nose earlier. One of Chet's men then stabs Richie's hand as Seth pulls out his revolver and shoots one of the other men. It is obvious and easy to tell that the bullets supposedly hitting the men aren't causing any kind of blood or damage, etc. In fact, it almost seems they are blanks.
Continuity mistake: As Santanico begins her dance, she swirls her cape. On the third "swirl" a snake appears. The camera shot goes to behind her and the snake's head is working its way up her back. Then in the next shot, the snake's head is round the front and works its way upwards towards her head.
Continuity mistake: The scene where the vampires in the Titty Twister bar start devouring the customers. George Clooney confronts Salma Hayek. She taunts him and he shoots her. When he does this the jacket falls open to show he is wearing a white shirt underneath. However, when she comes back to life a couple of seconds later and punches him to the ground, his jacket falls open again - only this time it is a completely black shirt underneath.