And yes, there is a big hole on the east side of the map. It has a lot to do with that it's generally easier to complete river sources before being able to complete the lower parts of a river. So, much of the lower Ob and Yenisey basins I just haven't done, because I've been working on the big circle of mountains and uplands that give birth to those huge river systems.
This shows, now, 24 of the maps I've drawn out ... and the detail is definitely starting to decline. That's a damn shame.
Does anyone understand now why I scoff at the Greyhawk map?
Incidentally, for the observant, you might really see now how that 60 degree turn in the map to keep with the curvature of the earth distorts the shape of Russia, just at the point where it meets Europe (specifically, the thrust of land between the Baltic Sea (mid-left) and the Black Sea (bottom left).
A complete list of all maps can be found here.