Using the exceptional "WW2-what-if" simulator that is Hearts of Iron 2, I have discovered the following, during the AAR in my signature:
If the USSR had devoted massive resources to battleships in the pre-war years, Germany would have found itself forced to match the red naval threat, and also built more battleships and sooner. This would have been done at the expense of aircraft and tanks. Since the Soviets also sacrificed aircraft and tanks to build the
Sovetsky Soyuz class, the end result is turning the Eastern Front into an infantry slugfest. In those conditions, Germany gets crushed even faster, and Red Europe becomes a reality sooner and in a larger scale than OTL.
On the other hand, US, UK and Japan also supercharge their naval build ups, to unpredictable results (i.e. "I lost the save files").