I've almost finished creating my zombies map based in the multiplayer Combine map, should be ready to play soon, just gotta fix it because I accedentally broke the map at the last second (like usual).
 
It's a one room map based in the centre point of Combine, although it branches out the slightest bit onto other pathways, kino style teleporters and soul boxes which unlock end game which which is one of the issues im trying to fix.
 
I look forward to finishing it and hope everyone else likes it.