The table-top role playing game system GURPS (General Universal Role Playing System) is a system which provides rules for any conceivable action, possession or ability a player can think of.
Tonight Blair thought of ramming his virtual boot into the head of the NPC (non-player character) which was lying on the floor at his feet. He rolled his dice and succeeded so well that our Game Master had to refer to the Critical Head Blow table.
Sometimes a vivid imagination is lots of fun. Sometimes it's best not to share. No matter which it is, GURPS has an answer.
Lets just say the sound of the cracking skull was featured in the Game Master's cinematic desription of the poor man's death.