Not really, once the Battle of Midway was done, the Japanese capacity for a naval invasion was non-existent - Doing so would have left Japan open to the US main fleet.

Russia had assistance from the Allies, but primarily the US. Militarily, the Russians were largely dependent on three factors for victory, disposable man power, their own capacity for production (notably of artillery and tanks) and the German military's inability to properly re-equip suitably for defence following the halt of the blitzkrieg style assault.

A problem the German military didn't have in Europe, where the initial speed of their attack and rapid advance led to them overrunning the European forces.

However this wasn't the case on the Russian front, and the German military had monumentally overstretched their supply lines, and were ill equipped to defend territory and for winter - allowing the Soviets to regroup and counter attack.

The Germans were also plagued by the soviet backed and organised partisans operating from within Poland right through the Ukraine and Russian territory - who specifically targeted the supply lines.

Add that to the Russian Scorched Earth Policy, and the Germans war effort was doomed to failure by the end of 1941.

At this point the UK forces were desperately re-equipping in the UK and incapable of opening a second front in mainland Europe.

Yes. Pretty much, the only difference would be that Russian would have been a far more popular language in Western Europe.

By the time of the Normandy landings the Soviet had won the Battle of Stalingrad, Moscow and Leningrad and rolled over the Germans at Kursk in July 1943 (the last real German offensive on the Eastern Front).

Although in fairness, British spies did tell the Russians where the Germans would attack, and the invasion of Sicily did draw down German reserves for Kursk somewhat.

But the reality was that it wouldn't have made much difference. The second front the UK and Allies launched sped up the war in the East, and almost certainly prevented the Russian war machine from 'liberating' all of Europe.

The Germans just couldn't cope with casualties in the way the Russians could.

In a protracted war with only Russia, I believe that German superiority in innovation would have seen Russia surrender when the Germans dropped H bombs on their major cities, They would have also developed long range missiles and jet aircraft. Even with superior man power the Russians would have had to overpower the Germans within say 6 years to be victorious.

This is all a stretch because it is unlikely that a full scale war between two major nationns would have occured without escalation.

Long range missiles - yep, they were way ahead of anyone on that. Jet aircraft - yep they had a head start, so again completely plausible, except the German Jet aircraft had seriously short range. But the H bomb? Is there any evidence to say they were close to developing that?