Classic Deadlands has several hit locations: head, torso, each arm, and each leg. Damage to each location is tracked separately, and damage is cumulative to a location, but not across locations. So a character with light wounds all over isn't too bad off, but a character with a serious head wound is in bad shape, even if he's uninjured elsewhere. In general, characters can die only from head or torso wounds, though bleeding from other locations can also kill eventually. Some locations can effectively take more damage than others (being shot in the arm isn't that bad barring a high damage roll - being shot in the head will almost always be serious). Normally, hits are randomly allocated by location, but they can be aimed with a penalty.

Buffy has a whole slew of different combat maneuvers already worked out. So, stabbing someone with a knife is this maneuver, decapitating them with the knife is a different one, and stabbing someone (say, a vampire) through the heart is a different maneuver still. More difficult maneuvers tend to have penalties associated. Also, there are minimum damage thresholds. So, if you stake a vampire through the heart, you get to do a lot of extra damage - but only if that extra damage would be enough to kill them. If it wouldn't be enough, then you just miss the heart and do normal damage.