Revealing mistake: When Montoya uses a spear to toss the vampire woman from the prison door into the sunlit street, it is an obvious dummy that has been used. First you see the woman stumble out, and the first flames shoot out of her, then the angle changes to a close-up of her as she is engulfed in fire. In the close-up, she has become bigger and rounder, and does not move.
Revealing mistake: When Montoya wakes up in the jeep after being bitten by Katrina, you can see the edges of the fake skin placed on his neck where the bite is. It reflects the light.
