The ground needs a lot of work. It's completely flat, lacks tile variation and the stones look a bit out of place, mainly because they are so dark.
The light rays/balls/thins are awfully random and really ruin your terrain. You'd be better off if you just removed them.
A few pictures with the camera being closer to ground and facing upwards wouldn't hurt, the gameplay-view like angle that you used is rather boring.
Moved to the terrain forum since it doesn't meet the standards of the art gallery.