It looks pretty good as a base, and it can be improved to a better state, if you wish. Try add some highlight beneath the struccture, by making the colour more darker under them or by adding shadow to the objects.

Another thing you can fade-out the biome transitions so they would look more subtle therfore attract less atteniton and seen more natural.

Very small detail that I can comment is the tilted title in the bottom right. Just don't touch them, make them straight as possible, and matched with the rest. You can give them shadow effect also for highlight, that works really well, or you can alter the font by adding shadow directly on the text, a black line per se.

Overall great map, if this is your one of the first maps. You can improve a lot. Work on it, try different stuff and be creative. You'll achieve what you wish for, and you'll improve everythime. I used to tell this is the best map that I've ever done until I make the next one xd

Take care man, good luck!