Eh, there's a simple enough reason to assume the German military machine (which includes stuff like leadership, organisation, etc. besides the actual troops and equipement in the field) - until about -42 or so they kicked the rear end of anyone they could actually get their hands on. The Brits they couldn't, as the Channel and British air and naval superiority made any edge in terms of land army irrelevant; the Soviets they tried very hard to, but the buggers turned out to have just plain too much material they could afford to lose and territory they could afford to give up (I understand military jargon knows this as "strategic depth") to obligingly drop before the Germans exhausted themselves.

That aside, early in the war the Red Army was something so pitifully undequalified for any real military application it's just plain tragic. Stalin's political fickles and mass purgings had pretty much crippled it, most of its equipement was crap, and the troops supposed to use them had only a very vague idea of how. What quality remained in the officer corps was pretty effectively throttled by direct political control over their operations in the form of the infamous Comissars and other political officers directly supervising everything.

There's a telling anecdote about some low-ranking courier or somesuch who was told to take a message to some officer in his HQ, and given a pair of NKVD soldiers as escorts since others weren't available. (For the record the NKVD were political troops under Party control, and usually the ones who got to act as "plug units" to keep line troops from fleeing; the Germans found them fanatically stubborn adversaries.) When he entered the hapless officer thought he was a political officer come to execute him for failure, and pretty much pleaded in tears that he hadn't done anything, had only followed orders, all the mistakes had been made by someone else, etc.

Ought to tell something about how well the command structure worked at the time. Stalin gave the military a looser rein as a sort of reward once the front began to stabilize, which proved to be a generally good move.

Compared to *that* the German equivalent was a smooth-running Swiss clockwork crafted by a master of the art, even when Hitler was telling his hapless commanders to do stupid things.

The Soviets were actually pretty familiar with the Blitzkrieg idea - they pretty much invented it around the time they were secretly doing joint military research with Die Reich. However, Stalin's little political maneuvers put the pioneers of the idea into the camps and restored the organization of Red Army assets to the same, obsolete standards as about everyone except the Germans used at the early parts of the war. Once the Blitzkrieg idea (the Soviets called their version the "deep combat doctrine", apparently) got proven to be workable in Poland and France Stalin hastily ordered its adoptation in the Red Army too - and when Barbarossa struck the hapless army was in the middle of reorganisation, and to boot one carried out with the usual Stalinist adminstrative competency...

No wonder the poor bastards didn't do all that well.

As a side note, the T-34 was a bit of a miracle piece of engineering. Not by any particular sophistication by any means past the sloped armour; German tanks for example had by far superior gunsights (although it didn't hurt that their crews were actually *trained* before being sent to the battle either...), and the Soviets never had anything akin to those prototype elevation gyrostabilizers the Americans built into some tanks. But it was fast, sturdy, reliable, had decent enough firepower, and was easy to produce in bulk. The /85 upgrade, although it apparently reduced speed and operational range a bit, provided the sound basic design with sufficient firepower increase and some other fixes (like having a three-man turrent instead of two, leaving the tank commander free to concentrate on his main job) to keep it perfectly battleworthy until the end of the war.

The only serious competitor in the same wight class, the PzKpfW V Panther, was overall better, but had an in the context crippling flaw - it had about as three or four time as many parts... And we all know how good straits the German war industry was generally in to begin with. In general they seem to have had a bit skewed, over-engineered approach to hardware developement their factories couldn't quite cope with.