Pros:

Well done, unlike most pony weapon skins
Detailed
Not too bright and colorful, so it doesn't look too out of place

Cons:

None

Conclusion:

Unlike most pony weapon skins, I really like this one I will probably be using it. A lot of detail went into this one, and it doesn't look too colorful, which means it isn't going to look out of place in the game.

Pros:

Portal-esque style.
Challenging, which is something I wouldn't expect from Left 4 Dead.
The finale is cruel (in a funny way)
It was played by the yogscast

Cons:

None

Conclusion:

It was amazing