This is very good Martin. The blistering on the tiles is lovely, the blood is very fresh, and the map is uncluttered and the colours work together.

I hate to give criticism in the Finished Map thread (the battlemaps Work in Progress forum where people post maps for critique is elsewhere) however since you explicitly ask for it:

1) there are white gaps between your ground and wall tiles where you mislaid them. Fix this by adding a layer of solid dark grey behind all the other layers. If you placed each of those tiles by hand on GIMP I can tell you how to do it more easily next time.

2) the seperate wall segments look a bit odd to be honest, but this can be easily fixed by taking one segment, removing the edges and making it TILEABLE, and then TILE it horizontally for an unbroken line of bricks (I can walk you through this if you like) and then cut/past/rotate.