Pros:

Long campaign
Great use of panic events
Non-linear
Interesting locations( I really liked 4th map with walking on these big silos )
Challenging
Funny finale

Cons:

Sometimes you don't know where to go
Most of terrain is flat ( in woods it looks terrible )
Lack of detailed areas

Conclusion:

This is really good campaign & challenging. You should try to make a bit smaller areas but with more details.
Ah and put more lights & marks for player to know where to go.