If you’re a Portal 2 fan, you might enjoy this underground themed custom map by yours truly:
Some of my proudest modding work for Zombie Panic! Source is “Zomboeing.” This was an ongoing project for about 4 years. It started out as just some fun, but then later was nominated to become an official map for the game by its developers. Sadly, that never came to pass. But you can still download it and give it a tour! View installation instructions here.
Although less popular, I still take great pride in the production of this other Zombie Panic! Source map: “Circumvention.” View installation instructions here.