Your brushwork to be honest is just far too simplistic and the lighting is far too bright to the point where it really does look like fullbright is on unless your in the tunnel you created.
Taking your map in as a whole, its not really that good. far below the average thats available on this site. Spending more time on making unique designs and layouts and also some more prop work and brush work to advance the style of your maps would get them noticed and popular.
Theres still hope for you, Check out the available tutorials that are here,