Because the military leadership of other nations were mired in lessons learned from the previous major war, as always. Those lessons were, hunker down in an impregnable fortress and let the enemy beat their heads against it. So the Nazis simply went around them. easy.
The zeppelin and the blitzkrieg.
Because they are effective, accurate weapon.
The British did. They were trying to deceive the Germans into believing they were for transporting water to troops in places wheeled vehicles couldn't go.
In World War 2 the Germans introduced the V2 rocket, a terrifying new offensive weapon. In WW1 poison gas was considered the most terrifying weapon.
Zepplins and U-boats.
Zyklon B
The British tank was superior and in much greater numbers than the Germans. They helped to terrorize the Germans in the lattter stages of the war. The Germans, totally underestimated the potency of this new weapon.
V2 rocket
Ships
During World War I the Germans used many different types of naval weapons including a large fleet of battleships. The most effective naval weapon that the German army had was the merchant u-ship submarines.
Effective Weapon - 2013 was released on: USA: 1 August 2013
The Thundergun.