What were the positive and negative effects on weapons in World War 1?

World war I ultimately brought about the evolution of real machine guns. There were MASSIVE amounts of casualties because the opposing armies at certain points would leave their trenches and charges across the field only to be cut down by two or three men on a large machine gun. Other weapons came to be but largely, this weapon killed more people than anything else. Also, WWI was the beginning of aerial warfare. In the beginning, pilots would have a gun with them when they took flight and shoot at each other in the air.