Pros:

Fairly solid
Not boring
Has potential

Cons:

Some low res issues, specifically on the far side of the broken bridge where you first enter the sewer tunnels.
Glitch on the map with the fire, for some reason it started my friend and the bots in the finishing safe room instead of the beginning one, they all died on the previous level maybe that's why?

Conclusion:

Like has been said before, a little optimization and some little fixes and I think you got a good campaign. Oh, one other thing the map with the fire in the building was really short, maybe incorporate that into the previous or following map and make it a 4 map campaign.  The final map had issues too with the sky just being black and flickering and gray blobs.  Also the finale was real easy.  Maybe do something different with the ladder to the copter, change it to be a "fuel up the chopper" type finale like the finale of Dead Air.  Overall I'd say it's a solid C~C+.

Pros:

Great detail
I liked the cheesiness; it gives it a real B-Horror flick feel
The puzzles were kind of neat, a nice detour from the same old same old.
I think overall it was really well made, I didn't notice any reused maps or anything a lot of others do.

Cons:

The witch thing was a little over the top, but still fun
The tanks seemed real easy to defeat, no real challenge from them.
The custom voice acting. LOL, it was bad, sorry.

Conclusion:

I had a great deal of fun playing this.  I think this is one of the few custom campaigns I will actually look forward to playing again.