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: 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.
Continuity mistake: At the end when Seth drives away, we see Kate holding a bunch of money in both hands. The camera angle changes and now both hands are her hips, no money in hand as she walks away. In fact we see no money on her in any way. Where did the money go?
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. (00:55:20)
Continuity mistake: When Richard bends down to pick up the keys in the motel room, we get a shot of Kate's painted toes. Later in the RV, her toes aren't painted.