I really like the worn parchment effect... almost looks like it could be deer skin or something like that. Definitely an interesting texture to the background.

I agree that it's a bit dark atm and could use some lightening up, and that there could be some more separation between water and land. I was a bit confused as to which was which at first, until I looked at the labels. Looking closely, I can tell you're using different colors for different elements. I think maybe because it's so dark overall that the coloration is a bit lost.

Great start so far though!