Hmmm....

From the comments I've read, some of them like silent tanks spawn adds more thrills to the players or even scare them if one has spawned near.

~Cons:~
1. Always happen in finale, when using plugins that spawns extra survivors and even when using only 4 by default, they spawn under the saferoom and then results to mission losses over and over again until they all spawn in saferoom.
2. Map design was not my liking. Some where just bland, few look like empty.
3. Finale map had a very short space/room to hold off especially when more zombies spawn from different rooms.
4. If you stay close to one of the rooms, no zombies will spawn there through the end but they will in others.
5. Paths/Routing should have been hard but not to get easily lost.

~Pros:~
1. Silent boss spawns.
2. Invisible blocks in staircases so players could find the right way to go and shut the alarm off.
3. Weather.

It could have been better if L4D1 survivors set was used to this campaign and remake the finale so that the rescue vehicle would be like the one at the beginning of Dead Center, making it look like L4D1 were rescued first while L4D2 was left at the hotel's roof.