Pros:

Good port.
Decent options of where you can stand for the finale.
Crowbars everywhere (my Freeman senses are tingling).

Cons:

A few bugs.
Very easy, especially the finale.

Conclusion:

Bugs I noticed: 
On the train tracks, zombies would go on the left side of the stationary trains and just stand still between them (despite no invisible wall).
When reaching the bottom of the elevators and reaching the walkways, the tank and other infected couldn't get up to the walkways, despite there being a way up.
The tank can get into the train in the finale (not necessarily a bug, but it's inconsistent with what other campaigns do).
If you jump straight into the vat of water you die instantly (even though it's quite a short drop into water). If you jump on the rim of the vat and then the water, you're fine.


Overall very enjoyable. I do like seeing the HL2 maps made into L4D campaigns, and it's good to see them done well. Might've been cool to see some evidence of Grigori being there. I'll definitely play this again. It was certainly well done.