I like this idea alot, its refreshing not typical in the least. As a playing board its clean and no nonsense, and i like the use of texture. However, i'm not sure the sand stone color jive very will with the dark and luminescent "dungeon squares" Tthe thick black lines are bold but also obtrusive against the sandstone color. I would play around with the color and saturation of the background and see what happens, maybe something more stone like grey or marble would serve you better for the mood of the piece. Just my 2 cents!