The Sega Saturn version of the title was released with the subtitle of "Graveyard Edition". This version features a few exclusives such as a difficulty select (ranging from normal to bloodthirsty to cannibal), a new in-game feature that involves items and power-ups that slowly drop down from the top of the screen that can be shot and collected, and all new "in your face" zombie attacks. These attacks involve a zombie that literally pops up right in front of the "camera" and attacks the player. They can only be killed with AP rounds or Datura rounds.
Source: Wikipedia, "Corpse Killer", available under the CC-BY-SA License.