<< One shot to the nose can drive part of his skull into his brain]/Q]
Actually, it's the area under the nose between the nose and the lips that you have to be careful of. That area of the skull is pretty fragile and can cause collapse/damage that can lead to death. Also watch for the temples (sides of the head.) Then there's the solar plexus (soft spot right between the ribs and above the stomach.) Those are the three biggies. You can probably get away with cupping your hands and smashing the sides of his ears. Hit him hard enough, and it will cause some bleeding, great confusion, disorder, and he'll probably be on the ground for awhile. If you do it wrong, I suppose there's a small chance his hearing might be impaired. If you're not going to exert much force, go ahead and go for the nose. You can cause a nose bleed or something without too much force, but if you nail the bridge of the nose or the philtrum you might be in trouble. So, to answer your question, it's not that hard to kill someone if you know what you're doing. If you don't know what you're doing, you probably are going to wind up missing those spots anyway. Oh yeah... try to stay away from the throat a little bit unless you're choking him out or something.
Then again, how about you solve your problems peaceably like an adult?