A big difference that doesn't get mentioned enough is, most all game run around naked and you have the opportunity to take the shot or wait for a better one. You are also after, for the most part, a particular type of animal so you can match your cartridge to the animal. A human will probably be wearing some sort of clothing (perhaps a lot of clothing, perhaps not) and will probably not allow you to choose your shot. Your bullet may well be required to pass through multiple layers of clothing, bone, and who knows what before ever penetrating to a vital area. All this while your foe is attacking you (if he isn't, then it's probably murder and not a suitable discussion for this forum).