They defeated the Nazis by throwing conscripts into a meat grinder regardless of whether they even had a weapon, and by threatening to shoot them if they tried to retreat.

Enemy at the Gates is not a documentary, it’s a propaganda film. In true fact while the Soviets did have a large number of conscripts and did suffer supply issues early in the war, at no point were they sending under-equipped battalions into the front line to die for no reason, and the thing about shooting those who retreated only applied to officers who ordered a retreat without proper cause (you’ll find that every other army in World War 2 had a similar protocol).