Jungfraujoch is a survival map for Left 4 Dead 2, initially designed and built within 11 days as part of World of Level Design’s January 2010, 11-Day Level Design Challenge, and has since been updated. The contest had followed a theme based on the Winter season, along with posting progress work each day in the forums.
I barely missed the contest deadline due to a brush not exactly being on a grid point - which took me a while to track down. But I did continue and finish, and later came back to polish it beyond the 11 days. In terms of gameplay design, my greatest roadbump was getting the difficulty on par with Valve's maps; I was lasting an average of 7+ minutes without trying. After adding in a break wall and tweaking the navmesh, I'm happy to say the average time in playtests significantly dropped and stopped receiving feedback about the difficulty.
You can check the forum log here.
Modeled and textured the environment, as well as lighing and navmesh construction. Props are Valve's.