Pros:

Yeah, i'm voting this 100 because of idiots who rate quality stuff like this 40.  

There are no custom melee weapons in this campaign. They are simply not there man.  Check your botched riot shield mod install.

 L4D is not a single player game.  It was never designed or intended to be played this way.  Single player mode is sort of an afterthought game mode for people without friends.  Get some friends.

Cons:

This rating system is a complete joke and something needs to be done about it.

Conclusion:

That'll do I think.