Pros:

-Canada! Not only for the mention, but the Left 4 Dead Universe doesn't talk much about anywhere other than Eastern US, so this change in terrain makes for an excellent addition, should be canon, somehow.
-OST: This makes for any good map/campaign, a soundtrack that speaks for itself.
-VCs used in the most hilarious of ways, with multiple outcomes for each route taken
-Multiple routes, although not abundant, choice is always a difficult but fun experience for players.
-Original Feel, on a new engine build. Playing though this, the only difference I feel between this and L4D1 is the new weapons, aside from the obvious lacking effects mentioned by the developers. 

Cons:

-The Campaign makes some very unrealistic changes in scenery, and much faster than most campaigns, the lack of progression can often confuse players, especially if they join mid-game
-The lack of ALL the content that L4D1's version had was disappointing, but explained and understandable.
-I can't express how saddened I was when this campaign didn't have a custom finale, for such experienced developers, it seems a bit lazy (for lack of a better word).

Conclusion:

Very good campaign, a custom campaign for everyone's list. This one has it all folks, save a few things we miss from L4D1, you'll want to play this campaign. Get some friends, and some marshmallows, this campaign is sure to be a fun time.

Pros:

-Conclusion to the whole "Survival" idea
-Custom ST
-Canon with the actual Helm's Deep
-Different methods used for "survival", and differently shaped places makes for a fresh feel every time the console says "FALL BACK!"
-The addition of the Original Survivors making an appearance is always more than welcome.

Cons:

-Bot nav, although fine-tuned doesn't feel right, bots sit back and watch more than they shoot zombies, up until the point where you get inside the keep.
-The ST gets very loud at some points

Conclusion:

Excellent map, with a lot of thought put into it. Although unoriginal in terms of layout, still probably the best survival map in the history of L4D. 

Pros:

-Very interesting new mechanics, several stages of this makes for a great micro-campaign.
-(Although loose) Custom VCs for the survivors are used.
-Overall Quality of the campaign is excellent, definitely continue your work on this.

Cons:

-Repetitive, especially if played on SP
-Not enough infected doors/spawns 
-Absolutely no vertical components

Conclusion:

The micro campaign is a very interesting concept, to say the least, and really stretches a survivor's mind to work in new ways, but the lack of infected spawns can leave this uninteresting and repetitive. I like what you're doing with this though, some work, and this could be an excellent finale for a longer campaign.