Simon's death is the first death the readers witness in the book and it is a climactic scene. The purpose of the scene is to show that the boys have now descended to a new level of savagery and Simon's death is a symbolic killing of the beast that has been terrifying the boys. The description of Simon's death is drawn out for the climactic effect that illustrates and emphasizes the horror of what is happening. By contrast Piggy's death is abrupt and ugly. The purpose is to show the complete disintegration into savagery. While Simon's death still held some degree of civility because the boys were already in a frenzy and the storm helped to obscure Simon and his words, there is no such obscuring of Piggy's death. It is blunt and brutal.