Describe the german tactic of blitzkrieg. what effect did this tactic have during the first two years of world war ii?

Blitkrieg was a tactic used by the Nazis. Essentially, it involved using ground troops, supported from the air using planes. It involved concentrating a ton of firepower all on certain select areas.
It allowed the Nazis to quickly overrun much of Europe very quickly (Poland, Belgium, the Netherlands, France, Denmark, Norway, Yugoslavia, and Greece).
It was also used later by Rommel in his campaign in North Africa.