What makes the difference between Bartenders and most other vampires is the fact that they can store their souls in bottles (these are called phylacteries). These phylacteries will bring them back to life if you shot them down; because of that, you have to destroy the soul storages first and then take care of the bartender.
Bartenders can take more hits than usual for vampires, taking two headshots or several more shots to the body to go down. Shooting them for afar is recommended, since bartenders can endure up to 17 punches. Their phylacteries surely shatter quicker, with three punches. When they "die", a blue and white link that connects the phylactery and the bartender's body will appear; if the player fails to destroy the phylactery before the bartender revives, he will slowly get up accommodating the broken bones in his body and will continue to roam the room again or shoot the player if he is in range,
For some reason bartenders always seem to speak in caps.