Pros:

Amazing detail
Beautifully crafted
Stunning graphics and colors
Bright, airy
Intelligent design and execution
Professional

Cons:

None that are worth mentioning based on the final presentation

Conclusion:

The campaign is as close to "art" that you will find.  Valve, you may want to hire this guy :-)

Pros:

Fun to play
Hard in spots (endless hordes) even on normal
Interesting in some cases
Long (very long as it took us 2 nights of 3 hours total play to finish)
Some interesting places to visit and explore
Good design
Good effort
Fireworks everywhere to use to distract the hordes

Cons:

Directions could be better (but we like to explore so this isn't really a "con"), like if this was real, would you expect "arrows" pointing which way to go?
Some glitches (exploding garage that doesn't) - we were able to get it to explode by shooting a gas can in front of it (I actually liked that if that was what was intended)
More supplies are needed
Some unintentional spawns as previously noted

Conclusion:

I think some of the reviews are a little harsh here.  This isn't bad and perhaps if it was advertised that the campaign was created intentionally to have things not happen (i.e. the garage door), that would make it more palatable to some.  We'll play this some more and I may update this at a later date.  I give the author a lot of credit for trying.  Creating maps is difficult and if we beat the folks up, they won't do it any more.  I encourage you to keep going - this is a very good start.

Pros:

Amazing detail
Great flow
Some really scary surprises (like jumping down into the water only to find a tank there!)
Looking for keys, coins, items
Large area with many places to investigate
Great spacing of supplies and health packs (as you'll need them on Advanced)
Great work

Cons:

Bots (usual)
In first map, the only bot (we had 3 players) didn't jump down into safe room (we had to kill him to progress to next map)

Conclusion:

Imaginative, sprawling, well planned, well executed campaign that will provide hours of fun for those who like campaigns that double as scavenger hunts.  Will play many more times.

Pros:

Great design
I particularly liked the option to turn the lights on (start the generator) or leave them off to search out and kill zombies (rather than having them swarm you) in several maps
Very good AI and navigation
Enjoyed reading the custom graffiti
The scenery design was exceptional - great and meticulous map design
The finale was hard but we like hard (even on advanced) with only a little room to run around
Good supply locations, many places to search
New locations – not a rehash of what others have done (original)

Cons:

Some minor bugs and issues noted on other reviews

Conclusion:

Exceptional effort and campaign with only a few issues.  This is playable multiple times and we look forward to exploring it again.  Great job!