Pros:

Vocal interactions in the environment.
Took time to create City.
Technical work is high.

Cons:

Poor level design.
Every level is too long or large to a fault.
Pacing is bad on every level but last.
No clear paths or direction.

Conclusion:

This is a great disappointment. From all the reviews I was expecting something well throughout but it’s not. There seem to be a lot of tactical knowhow but didn’t take the time to focus of the fundamentals of level design. The player shouldn't get lost so much. The levels are way too long, they need to be broken up. This campaign should be 7 maps or cut drastically. Levels attempt to have multiple paths but because there is no clear direction of where you’re going to begin with players are just lost.  There other problems that I can mention, like wood that takes many clips of ammo to get out of your way, but this is getting long.
The finale is a scavenge map. It works but I can’t say it’s successful.

The campaign is “Percent 84”, but it’s only the last map and it’s not that interesting. If you’re going to name a location in the title the majority of the campaign should reflect that. Like “No Mercy”
I think what ultimately hurts this campaign is it feels like a port from L4D2. 

This reminds me of the first release of “Dead Before Dawn.”  
Like “Dead Before Dawn” it needs the creator to be willing to change. Levels need to be trimmed/cut  and path/goals need to be defined. 

I feel that this campaign was just thrown out. Its a early Beta thats listed Final