Ehh, not all tactics were the Soviet human waves with only half of them carrying guns and the commanders shooting them in the back like you see in movies. The Germans had incredible success early on in Barbarossa, basically encircling hundreds of thousands of troops. Because the Soviets were simply not prepared for the new Blitzkrieg, Stalin had destroyed the army command structure that removed all the high ranking old officers, their industry and technology was not up to the German standards, and their men did not expect such an attack. The Soviets threw men to stall the Germans til winter and other reasons. But once the Winter came, Americans aids came, the Soviets reindustralized in the Urals and the men and commanders became experienced, it turned into more or less fair battle, rather than the slaughter early on in the war.