Challenging
Very long
A lot of new props and tricks (loved the radio!)
Excellent finale concept

Way too much ammo, not enough throwables
Littered with graphical glitches caused by incorrectly placed standard props
Boring interior places, everything is square
The ending wasn't really on par with the finale
The English is pretty bad

This campaign has maps that develop a lot vertically, upping the challenge since survivors have to constantly watch their step. Despite way too many things looked wrong, it was all extremely fun.
Oh, at a certain point, map 2 or 3, I don't remember there's a sofa, an extremely inviting sofa, but jumping on it will cause the stuck-while-in-falling-animatiion glitch. Annoying.

All original and new panic events.
Gauntlets? In my L4D?
Huge maps leading to two tanks per level.
Great ammo balancing.
One of the most entertaining finales ever.
The logs and medical clipboards, although nothing really original or never seen before, add some depth to the campaign.

All exterior zones are poorly detailed. Some buildings suffer from the same problem.
The finale's workshed is way too secure. Breakable walls should be added.
Missing textures for the explosions on the bridge.
Sometimes supplies are so scarce you will be begging for a pipe just because you're tired of entering rooms with nothing of interest.
A few graphical glitches here and there.

The first time I played this campaign I totally fell in love with it. It makes me sad to see that a lot of people rated this low because they got lost. At this rate L4D3 will have a GPS system included so people can understand that if there's a road that's where they want to go.

Anyway, while i love it, it's far from perfect. Unless you have absolutely no sense of direction you should give it a try - keeping in mind it's an ''open world'', not a hallway.

Challenging
A lot of items hidden around the maps
Some nice props
Most maps get two tanks
Interesting finale activator and vehicle
Overall well balanced for advanced
Very long

Design is nothing exceptional, most locations are rather empty
Extremely redundant, all the places look like the ones before
Every panic event is either a switch that opens a gate or an elevator
The gates open way too slowly. For most of them we just had to wait, 'cause no zombies were coming either way
Bots fry themselves on the metro tracks
The final map is a bit too long
Very long

When my friend and I finally hit the rescue vehicle after 2 hours on Advanced, my feelings toward this map were a mixed bag. I loved the relentlessness of the constant hordes coming (5083 total zombies killed) and I had a lot of fun, but when I wasn't fighting zombies it was rather boring.
I'm not saying you shouldn't try it, just keep in mind it might leave you a bitter taste that you can't describe. I know it did it to me.

Very fun to play and nice to look at.
Good ammo balancing.
Extremely unpredictable finale twist.

Short.
Not very challenging, with the exception of the last panic event in map 2 and the twist in the finale.

Strongly recommended for a quick game (less than 1 hour on a first try).

Awesome design. Everything looks great and is well detailed.
Fun panic events.
If you survive a crashing plane you certainly won't start with 4 conveniently placed first-aid kits, a shotgun and a SMG.
Great props everywhere.
Multiple places to explore.
Challenging.
Extremely tank and witch happy.
Excellent idea for a finale.

A lot of the items found around the maps are static.
Map 2 is totally littered with pipes and molotoves.
A few minor graphical glitches.
The train/saferoom is missing textures.
Finale "vehicle" causes a random amount of survivors to die when getting rescued. (see below for details)

This map is just great. It was fun. It was challenging. The bots took a lot of damage on the barbed wire *cough*.
You can clearly see a lot of effort was put in every part of it. Totally recommended.

About the finale glitch: I completed it twice. The first time alone with three bots. Two of them died after getting on the "vehicle". The second time I was with a friend, the bots had died to the tanks, and we both died on our way out. Which was annoying.

Interesting maps.
Nice ammo and weapon shortage in the first map.
The relentless waves in maps 3 and 4 make it very challenging.
Twin tanks!

Nothing new concerning the design of the areas.
Too many locked doors that look like real doors.
The ammo shortage at the start quickly turns into an excessive amount of ammo piles, with a couple of exceptions in map 3.

Fun was had with this campaign, but it is far from perfect. Overall, it's still a thumbs up!

Excellent rendition of Doom's level.
Exploding barrels.
Use of keycards (although, some audio or visual reminder that a player has collected them would be neat).
All the graphics and props look the way they should.

Way too easy and short.
Bot unfriendly: they can't open doors and pick up most items.
No finale.

The amount of common infected should be *at least* doubled, same goes for the SI.
A finale should be added.
It was fun, but the kind of fun that lasts for only 12 minutes. Unfortunately I can't give it more than 65.
It's worth a go, but you won't be replaying this map anytime soon.

Amazing detail in the maps.
Difficulty extremely well balanced, although newest players will probably find it too hard.
Very long campaign.
Always fun to play.
Original traps and props.
Subtle story in the background.

The story is not enough explicited: most people fail to understand that this doesn't take place in the L4D universe, but the survivors are actually stuck in the mind of a kid who's having Night Terrors.
Sometimes there's too much ammo.
A guaranteed set of T2 before the "bucket event" would be sweet. Otherwise it's a bit too hard.
I wouldn't change them right now, but for a possible next map of yours I'd avoid long pauses like the monologues on the Stretching room or the "bucket" scene. After some restarts they get tedious.

Fun fun fun, fun fun. Get it.
Really. Seriously.

Excellent design
Huge, well detailed areas
Excellent gameplay, well planned hordes and events
Overall high replayability

Missing supplies in some of the saferooms can up the challenge a bit too much, especially if the players don't know it in advance and plan according to the "usual" rules
The lower part of the skybox in the finale doesn't look right
Bots have the usual problems with navigation

This is one of my favorite campaigns. Very recommended.
Please note: there have been *great* improvements on the gameplay since the version reviewed by Kilplix N Friends.

Nice design
Wide areas to play
Some creative ideas like the jukebox and the part in shallow water
Fun to play gameplay-wise

Most of the custom text on the walls and floors stands out and looks out of place
Rough skybox
A lot of graphical glitches (see through improperly aligned parts of objects, misaligned textures, etc...)
Clutter and detail in the wide exterior areas and some of the interiors is poor

Considering the gameplay only, this is a very solid map. But when you find yourself in a parking lot with less than 10 vehicles and square anonymous buildings all around, it really kills the mood. Detailing huge areas like these takes obviously a lot of time, and the author clearly rushed it. Not a gigantic flaw, but it eats some of those points that would have made this an epic map. Still recommended for fun.

Very challenging

Messy design
Poorly cluttered: the same few objects over and over
Extremely linear
Events started by walking in specific spots rather than by activating an object
Special infected can somehow activate the spots above
All in all, not much fun to play

I never like to pan a map like this, but it really shows that the author didn't put a lot of effort and creativity in making this one.

Great design and detail
Challenging
Exploding barrels

Quite short
Many problems with zombie and bots navigation: hordes occasionally couldn't get to us and the bots often stayed in place until the game decided to teleport them. Also, stupid bots don't know how to stay away from the electrified fence.

If you like your daily close quarter claustrophobic zombie slayage you'll definitely love this map. I couldn't find any ammo on the finale area, which can be quite a problem, but I didn't put it as a con since it might just have been me being blind.

Solid looks
Solid gameplay

Not extremely exciting so far, maybe I just got unlucky with spawms
Incomplete (this is not affecting my rating)
On the first map the oxygen tanks used to blow up the wall can incap the whole team. I don't know if this is intentional, but it was a very cheap trick. Incap one player - good fun; force a restart - very wrong.

I'll definitely check this campaign out on the next updates. You should too.

A lot of locations to see and explore
Excellent work in clutter placement
Original events and game objects
Good voice acting
Fun finale
4 survival maps

Bots going mad before the train event (see below)
The mounted minigun on the finale sometimes uses a wrong vertical position on the first person view (if activated when below it)
Survival map 2 acted weird (see below)

When you play this map you can see that a lot of effort has been made in creating it. A lot of locations that do not sum up to anonymous building and alleys, but rather a movie theater, a police station, and more.

For some reason some bots, in the room where you have to wait for everyone to get on the train to activate the radio, keep trying to get up the ladder that's used to get there, making it impossible to start the event since it's impossible to go back that way.
On another note, survival map 2 (the prison block in the police station) acted very weird: up to the 10 minutes mark the hordes kept spawning from the same 2 spots, leaving huge intervals of calm between them, up to 30 seconds. From 10 to 14 they used more spawn points, but still with long pauses. From 14 to 17 all hell finally broke loose. Past that I can't tell 'cause I was swimming in a pool of blood. It was kinda boring :/

tl;dr: awesome map. Must have.