Pros:

-allows for easy access to any mutation without having to wait weeks for it to become available.

Cons:

-numerous glitches, such as custom soundpacks not working in some mutations and the game just flat out freezing.

Conclusion:

Overall, this is an awesome mod, but it does still need some work done.

Pros:

+Looks Nice
+Feels like an actual L4D map
+Pretty difficult

Cons:

-None that I can think of

Conclusion:

I cannot really think of anything wrong with this map. Maybe, like others have said, add a title card at the beginning of the campaign.