The majority of the campaign is concerned with dispatching enemy alien characters, however human characters can also be attacked with melee weapons, explosives and various firearms. Enemies which are shot or stabbed usually fall to the ground and there may be a small amount of blood. During multiplayer gameplay, players can assassinate heavily armoured human characters by jumping on their back and twisting their neck, with a breaking sound. Some more non-realistic guns can blow your enemies up into glowing parts which disintegrate.