Pros:

the maps flow together very well
there's plenty going on so your not board
good pacing
the comic book feel is fun
it takes about an hour which is perfect
the bots behave very nicely
good looking envirnments
the finale has a twist

Cons:

i've played it through about 3 times and there's not much to complain about.
no infected including the tank can climb into the tunnel you come out of by the riverbed on the first board 

Conclusion:

a very fun campaign that turned out to be much higher quality than i expected
nice work.