Pros:

Woah! This is the most sexiest ze map i've ever played! It even exceeds the spacestation-series when it comes to looks and design. That's my opinion anyways.

Cons:

BIG "wtf"-map. NO ONE knows where to go. Since you chosed not to use point_servercommands, the map is VERY hard and confusing. None of the destroyable's sounds distinguish from all the other brushes'. That makes it even more complicated.

It also feels like a singleplayer HL2-map. The escaperoute is very camoflauged and small. You have to guess what to do next. E g when you have to find the button in the attic you wont know where to go after you have activated it, unless you heard the door moving. 50 players in a server with noblock deactivated will probably never be able to enjoy this map fully out. It wont work at all.

Your map also leaks. And zombies often get shot out of the map. Please try to fix that.

The map has ok theme, but it doesnt exactly feel cold for some reason. I guess its due to the sky. I'd suggest a more 'cooler' sky.

Improvements:

Point_servercommands!!! Tell the players what to do!

Please also try to make the escaperoute more visible. The map actually feels like a zm-map with a hidden nuke in it...

That fence on the street should also go. It's just annoying and unnecessary imo. It wont benefit to the gameplay in any way. Trust me.

Also try to fix the leaks. The fps is idd above average, but the leaks is prolly the cause of zombies getting shot out of the maps.

Notes:

The map works with 50 players if noblock is activated. Without noblock, i'd guess that 32 players is max.

That's all i could think of ftm. If i've forgot something, i'll let you know.

Pros: I like the city. It has very good shapes and is nicely detailed. This really gives a good feeling like your in a real city.
Cons: When I first played it I thought it was a zm map. The map is very confusing, I also had no idea where to go. You should even add "console commands" as when I tried to open doors and tried to nuke it didnt confirm that i nuked. Would be much better if u added those console messages.
Improvements: Add console messages and maybe something so you know where to go
Notes: I didnt check this ingame with other players, just on my own on my offline server.