Just read a book by David Porter, "Battle order of the Red Army in WW2", and what struck me what the extremely high cost in manpower and material that Stalin was willing to pay to win over the invading german. Also learned that the russians recieved, among others, close to 500.000 various military trucks from the US and Britian during WW2.
This author also found that Stalin's purge and exucutions of his very top to to low level officers during most of the thirties put the Red Army at an enormous disadvantage when confronted with a german invasion.
Also new to me, was the russian use of armed "Penal Units" from the Gulags, which was forced to be the spearheds of many russians attacks against the germans, as well as being forced to attack the germans, in front of russians tanks, and thus with their bodies, detonate any landmines that could otherwise harm the russian tanks. NKVD units would make sure that these armed "Penal Units" would do their "duty for the motherland", and if members of these "Penal Unit" survived, they might even be allowed to go free to become ordinary soldiers... It appears that over a million russian soldiers from these "Penal Units" formed from the Gulags, was used in this fashion. Most of them died.