The Soviets take the Germans by complete surprise. Operation Baroass is strictly a plan of offense, presuming the war will take place on Soviet soil, there's no recorded plan, however basic, of defending the Reich against the Soviet Union. I doubt the Luftwaffe will be shot up on the ground as heavily as the Soviets were despite being able to subject German airfields to continuous airstrikes, German reaction times should be better, but they remain outnumbered 4 to 1.
The Soviets have good tanks, and more of them, although as OTL Barbarossa shows that doesn't guarantee, there's a lot of rot in the Soviet officer corps and problems with equipment as well, it won't be the curbstomp that occurred in 1944/45, but the Germans will eventually be overcome and earlier than OTL. The Red Flag might appear over Berlin in 1942 rather than 1945.
The effects this would have on the post-war world would be interesting. America's role in the European War would probably remain that of a co-belligerent, Germany wouldn't be so willing to make new enemies when the Soviets are approaching Berlin, and FDR would still have a battle to directly involve American in a European War, one that looks like it's almost over anyway. Britain will be less debt ridden than OTL but won't be able to match the Soviets on their own, and certainly can't afford a Marshall Plan style recovery of Europe. France and Italy most likely go Red, even if they remain outside Soviet occupation. I can't see Britain falling to communism, although some sort of NAFTA style organisation would be necessary. The Pacific War will probably still happen, although it will be much quicker, with the USA, the British Empire, and the Soviet Union able to focus their resources on Japan much earlier. Hopefully that will drag the USA out of isolationism, if not the world may look very red indeed,
