Pros:

Great Campaign 
Good Weapon/Ammo Placement
Challenging 
Lots of environments 

Cons:

Lag at some points in the game.
Extreme Lag at the end of the game. 
Zombie Rush timing is a little to close. 

Conclusion:

This is  a great Campaign also to add great weapon placement. Mazes can get annoying buy there not so hard. The Hordes of zombies are set a little to close in some parts in some chapters. I do like the environments a lot. Only main problem is the extreme lag at the very end. But over all it is a great campaign.