The stonewalled_300709_1103.zip file you have requested: Maps Levels Missions / Survival Maps / Left 4 Dead Stonewalled Survival Map - 6.45mb is not available. Perhaps try browsing all files for the game Left 4 Dead and upload any files you want to share or are missing. This is the only information we could locate:
A small survival map focused on an abandoned military blockade in an urban area. The fighting is focused on a large fortified wall.