If you're still going to do some work on it, you should really take a look at the lighting. I like the idea of a dark map, but some areas are TOO dark. There are a number of deep valleys that are just totally black. This is mainly in the upper right, and lower left corners near the edge of the map. It's a pain to drop down in there and not have any clue where the bottom, or even the slope is and end up just cratering and losing all your speed.
Also, decrease the tile size on the grass layer, it's huge.
Other than those 2 things a wonderful map (again) :]