The Esturary Police do not like this map (and the River Police should be here shortly with a binload of warrants).

However, despite the fact that I am the sole officer of the Estuary Police, I dig this map very much! The Central Empire seems to be on the wane -- I bet there's a cool story behind that. This map makes me want to buy a ticket on the next steam rocket and get up there to explore!

I think your water gives too much of an impression of ice. It can't be ice, because you have rivers ... but we all know Mars has a polar cap and so I think the first impressions here is of ice. I think bevel effect hurts it; in fact, the bevel is a bit obvious all the way around.