I think what Tilt was talking about is the "bevel" effect on the rivers. I'ts much more consistent with a computer generated map than something hand painted like the rest of the elements. For the hills, they are nice, but a bit to large when compared with the mountains. Also, I would suggest grouping smaller hills much higher on the map surrounding the mountains themselves. They don't need to totally overtake the mountains and domintate the surrounding land, but a few here and there(make them smaller than the ones you have and shrink/remove the existing ones) in bursts would make this very nice. Also, I would suggest a small bunch of them be in the greyish color of the mountains where they are close, while the ones away from the mountains use the base background green color.

Also, you might want to think about shrinking the river as it gets closer to the mountains. It's going to get wider near the sea/ocean not smaller(well, in "normal" physics anyway).