broken, cuz of course it is...

Herby/Huck, you broke map transitions: (starting from individual maps works)
.
CModelLoader::Map_IsValid:  No such map 'maps/l4d_149_2.bsp'
changelevel failed: l4d_149_2 not found

.
CModelLoader::Map_IsValid:  No such map 'maps/l4d_149_3.bsp'
changelevel failed: l4d_149_3 not found
.
.
Also, I see what you were going for by increasing the rate of horde spawns as you get close to the safe room and having double Charger Spawns after the halfway point of each map... but couldn't you have done that with v13.0?

Getting better...

This is The Grave Outdoors from L4D1, but it never works when ported to L4D2 because it always results in neverending horde calls.  Play it on Easy if you're that curious to try.

EDIT:
OK v3.0 is an improvement in that continous hordes are gone, but many static hordes that last a long time have been inserted into maps 2-4 so it'll still feel hectic.
Still needs work though... bots don't want to pick up supplies unless you push them onto 'em.  For the elevator on map 4, they don't pick up the supplies in there at all even when you make them stand on top of 'em.