Lets look at kitchen knives. Most people, especially when looking at the trailer parks and small houses in the game, would probably not own a great set of kitchen knives. They will have a cheap set at best. Now kitchen knives are designed for cutting. And unless butchers hatchets (which would be cool *hint* *hint*), they are generally designed for slicing, and are not strong weapons for stabbing. Bearing in mind they are not designed for stabbing, lets look at the strength of human bone. Compared to concrete, it is stronger. Now you want to hit the skull, which if you hit on the dome of your skull, is the strongest structure, the same reason eggs are egg shaped. You hit a low quality knife onto a skull which on average is stronger than concrete and over half a cm thick, unless you have a huge force and a plum hit, you are like to either glance off, doing soft tissue damage (useless against a zombobble), or snap the tip off your knife leaving it in the skull and a useless knife in your hand. Also assuming you get it in the skull, it is likely to get lodged. If you are lacking in a knife sharpener, hitting bone every two minutes is going to turn it into a blunt object very quickly. Thicker kitchen knives and hunting knives would work because they would be better quality, generally thicker, and so have the strength to not snap along the blade, with hunting knives even being built not especially for, but with stabbing in mind. While things like hatchets, machetes, hand axes etc, work on a principle of a cutting edge with a lot of weight behind it, causing momentum to force the thin sharp edge through solid material with the weight behind it. These are the weapons that you would want, and even then, trying to pull your hatchet or machete from a zombies brain when you have another zombie trying to eat you is a scary prospect! As for cutting through the spine with a kitchen knife, forget it, it would be difficult to do with somone lying face down not struggling. The spine is one of the best defensive cages out there, because it protects probably the most important part of your body, the spinal cord. The brain could work fine, without the spinal cord it is useless. Like having a PC but the irreplacable ethernet cable is cut. It is designed to protect, and it does it fantastically well. The best way to hit a zombie would be through the ear with something like a sharpened screwdriver shank, again, an extremely difficult target when movement, adrenaline, and fear come into play. Or through the eye, again a difficult shot under stressful circumstances. There is a reason zombies are scary, destroying the brain, one of the best defended organs in the body, is no easy feat. I personally would like to see a climbing pick, perfect for piercing skulls, long handle, max force through a tiny point. But again, try and get that out of a brain in a hurry. It kind of seems to me that a one shot knife is very appropriate, if it is meant to represent slamming a kitchen knife into a zombie then leaving it embedded. The only suggestion I could make with that sort of thing is, is there any way that using a kitchen knife to kill a zombie would, instead of destroying it, make it disappear from your inventory and spawn one in the zombie you downed? Representing that after you kill it, if you have time to loot, you have time to pull your knife out! Great for solo kills, not so great against hordes.
