Pros:

Level design
Length
Atmosphere

Cons:

Difficulty (!!)
Too much supplies

Conclusion:

This map had probably one of the best level designs I've ever seen, the attention to detail was incredible. It really looked and felt very japanese and very unique. Great job on that!
My only (but very big) problem with this map was the fact that it was without any doubt THE easiest custom campaign that I played. 
We were able to run through it on expert/realism on 1 attempt without dying once which is in my opinion unacceptable. There were absolutely no challenging moments, there were supplies literally on every corner in such amount that it actually wasn't possible to use them all.
There wasn't enough zombies and hordes (we encountered a bug where zombies stopped spawning so we had to restart once) and tight situations.
It the goal of this campaign was to create an awesome visual experience then you succeeded and did a great job but if this was supposed to be a challenge then it's definitely not enough. I'd rate it 10/10 for design and 5/10 for everything else.
I also forgot to mention that you can completely bypass the finale by carrying the canisters to the generator before you start the mission.

Pros:

+ Good map design
+ Good difficulty
+ Great events
+ Almost everything

Cons:

- Maybe a little too easy at times
- Too short

Conclusion:

Great dynamic campaign, I don't think I've ever played so dynamic campaign. There were no dull moments, no too long segments or huge courtyards to slow everything down, only fast paced well put together maps.
I really loved the finale, it was one of the greatest finale maps I've played in a long time. I was a little disappointed in the length of individual maps and the campaign itself but adding to the length, other than that, I absolutely loved it. Maybe, it could've been a little more challenging.

Pros:

+ Great (mostly) outdoors campaign
+ Good supply of ammo and grenades, especially in regard to the difficulty
+ Difficulty!  If you are looking for a challenging campaign, I believe you just found one

Cons:

- Finale, see conclusion for more
- Sometimes, the difficulty, bear with me, see conclusion :)

Conclusion:

Okay, I thought that the map design and the way you made an outdoorsy campaign was absolutely stellar. It was definitely one of my favorite campaigns so far. 
On the other hand, it was very hard (which is a good thing by itself BUT =>), sometimes in a very artificial way. The amounts of hordes and specials on map 2 (it wasn't so apparent on other maps which were pretty easy) were absolutely staggering, good thing that there was the magnum on every map. At the same time the map had only 1 "impossible" moment - tank in the train with hordes and specials.
I wouldn't say that the campaign is unplayable on expert, we (2-3 man group with 1 bot) ran through it on realism/expert and it was great fun. I think there are many harder campaigns, but most of those gain their difficulty from a wide variety of deliberately "impossible" moments, which your campaign, mostly, doesn't, which is a great thing.
I have to say that the finale was a disappointment for me, I have no problems with gas cans in general but the town was so big and the distance to the car was just..too much. The hordes weren't too big in the finale but still, it was a nuisance rather than a challenge. I wish there was more to it, I was hoping for a "bridge" finale when i saw the beginning of the map. Nevertheless, the rest of the campaign was brilliant, thanks for making!

Pros:

- Good lentth of maps
- Right amount of suplies
- Nice difficulty
- Everything

Cons:

- I don't know, I really wasn't a fan of the super wide streets on map 3(?) but that's just me. 
Also, map 3 (the one with the trains) was much much harder than all the other maps and sometimes there were impossible situations. Like when a tank spawned in the area of the train tracks where you couldn't return to the streets and couldn't go to the roof because you'd trigger more hordes and another tank, sometimes 2 tanks, note: I was playing it on realism/expert. The roof part was definitely the most challenging moment from the entire campaign.

Conclusion:

Well made, well balanced map, great length, thanks for making!

Pros:

Amazing level design
Great creative ideas
Atmosphere
Old Apperture feel
Platforming section

Cons:

Can't think of any
Lower difficulty and shorter levels

Conclusion:

I honestly didn't expect that you'd add any new ideas or mechanisms and only use old stuff from QE1 but you thought of new and great stuff, massive kudos!
I felt like that Alpha test was the "old apperture" part as opposed to the new apperture from QE1.
The difficulty is way way lower than in QE1, while we spent literally weeks trying to do level 2 in QE1, we ran through this campaign in 2 attempts (realism/expert).
As someone pointed out before me, the number of grenade launchers was way too high, if there was 1 or 2 per level it would force people to aim carefully and preserve resources because the level would be impossible to complete without a grenade launcher, it would be kinda similar to keycodes from QE1.
The levels could be imo a little longer, the shorter levels, the easier it gets.
I absolutely loved the platforming section, the falling cars were a little annoying tho.
Anyways, great campaign and a worthy successor to the old QE1, it's 9.5 from me due to the lower difficulty and shorter levels, I'm very much looking forward to the final level. Cheers!

Pros:

Map design
Complex maps with many routes and hidden areas
Bug free

Cons:

Very very easy, even on realism/expert
Too much supplies everywhere
Too much daylight :)
Finale was a little underwhelming

Conclusion:

Great looking map, probably one of the best designed campaigns I've ever seen set in beautiful enviroments. The only con (which is unfortunately a huge one for me) was the difficulty, we literally ran through this campaign on realism/expert on 1st attempt almost without any medkits.
Basic weapons only (uzi+shorgun), far less supplies and ammo would make this campaign much more challenging and interesting. Also more hordes and specials would be appropriate. In the current state you can run through the quickest route and not worry about anything. If you had to search the map for guns and supplies and ammo, you would appreciate the great maps more and it would be a bigger challenge.

Pros:

Loved the earlier levels
Great buildup as the survivors progress deeper into the base
Well balanced, the difficulty is just right in the earlier levels
Loved the atmosphere of an abandoned military base
1st level with very few weapons
L4D1 survivors

Cons:

The finale might be a little too difficult (note: played on realism/expert), esp when the number of real players is less than 3
Nothing
Bots can be a little stupid on the ladder (last map) but it can be avoided when you position yourself properly

Conclusion:

Overall great campaign with some great level design, atmosphere and an unconventional finale..

Pros:

The best and most original mechanisms I've ever seen in a l4d2 campaign
Great puzzle elements
While the level design *might* look a little disappointing in the 1st map, it's actually one of the best designed campaigns
Awesome difficulty and challenge (note: played on realism/expert)
Everything, play it!

Cons:

The moment when you get to the ending of a level and realize that you forgot the passcode and you don't have and gas cans.
Nothing, this campaign is awesome.

Conclusion:

My all time favorite campaign, by far the most original I've ever seen, can't wait for the sequel. Don't play this map if you're new to the game because it. will. kill. you. especially on higher difficulties.
Also: 2 tanks in a pipe!

Pros:

Atmosphere
Original elements
Nice enviroment
Good level of challenge (but see cons)
Good idea with the finale and ending of 2nd map
Haunted house looks awesome

Cons:

Very unbalanced difficulty, 1st two maps are very well balanced and the level of challenge is just right (but the 2nd map can be challenging, esp. if you're unlucky) BUT the 3rd map is very very easy and the finale could use a lot more hordes, tried playing the final map 3 times and every time we were able to run through almost without any hordes.
Note: played on realism/expert

Conclusion:

Very well designed, atmospheric and good campaign, good distribution of supplies, weapons and ammo.
 1st two maps build up the challenge very nicely but the last 2 maps are too easy, making the whole campaign anticlimactic.
The 2nd map is one of my all time favorites, long, difficult, mostly without powerful weapons, I wish the rest of the campaign was so awesome.