My only suggestion would be to actually use more textures besides the ones that come in sauer. Granted, you'll have to link to those too.

I like the door with the skeleton and the thing that looks like a bridge with roof, those are to me, the more outstanding details of the map. I feel this map too square, even the terrains feels like there is not enought level of variation. The map is very empty in the walls, where you can just add some dimensions complementing with textures. It needs more textures (wich concludes in more details) and also, other colours of lights, like orange, blue, or yellow.

P.S: And its not a small map, i would say medium size.