New Weapons of the New Century
Initial chemical weapons were simple tear gas. Later the Germans would begin to use chlorine gas, which becomes acidic when in contact and destroyed the respiratory systems of opposing troops. Users of chemical warfare could wipe out the enemy without so much as a scratch.
The machine gun was a high-powered development, though in the early days of the war it was unwieldy and not without drawbacks. It took multiple people to operate a single gun, but it was powerful enough that it could shoot hundreds of rounds per minute and cause mass destruction.
Tanks were both a powerful offensive and an iron-walled defensive. Their gigantic size made them a hard opponent to defeat. Most of their power lay in surprise though, as they were still not very practical at this point.
Submarines were one of the biggest weapons developments in the war. Germany used their U-boats to cut off supply routes between the Allies. They could also carry supplies themselves.