the hell... realism? this games physics are a fluke. irl there is no possible way to decap someone with a fist to begin with unless your punch is above 120psi. arm rips and other body part rips are possible but with a lot of pulls and tugs. but if you really want realism with this you would have to up the dismemberment on the the head and some of the other body parts by a lot so that decap and some dismemberments losses/wins are harder to achieve thus making them special and the wins actually fair.