After playing on your map lonely and with another friend, i can finally leave some solid feed-back for your next version of this map or your future project.
First, for gameplay, i suggest you to create a better movement locations, areas for us - players - to pass through inside the houses. Some areas are too strait and while moving straight will be a pain in the ass for zombies. We can't make zig-zag to don't get a shoot in the hallways. I suggest you to extend the sides of these corridors for a better path for us. Otherwise, players will get in rage trying to hunt the survivors down.
Put player clip over the roof of the houses and in the garage. The blue house is good, since i can't climb over it but i still suggest to put it anyway.
There's too much kevlars and low amount of pistol and rifle ammo for a 16 players or full server. Create one more house and add more weaponry and ammunition for us - and some pills too. Would be perfect for a 10 minutes of survival time.
The window and door's borders are too simple. Put some detail around it. The lighting too. Create a different environment for your map, not only white light in the house.
The number of different textures is great too, i liked what you did. And remember to put two windows each garages too; we need more places to get inside of escape from the zombies ( And for us zombies, more chances to get the survivors. Only one door will be hard to get them. )
Add more details and brushwork outside too: create a simple road and sidewalk in the middle of your map and some trees behind it. Will make the map more alive and not only in a cubic area.
That's it, i would leave a 7 for everything what you tried to do on this map, improving what i said in this feedback, i would love to give a 9 or a 10 even :)
Cya and good luck!