Also undead nightmare is unironically one of the more unique takes on zombies. Not necessarily because they do anything particularly interesting with the zombies themselves but moreso because the closest thing to zombie Western I know of is a bug in the PS3 version of Fallout: New Vegas where an infinitely spawn of ghouls can occur at the test site. Never been able to replicate it on PC and I don’t know if it was specific to me or not.