Pros:

Unique campaign; difficult, but you feel a sense of accomplishment when you figure out a puzzle or find the right path.

Lots of dialogue from the survivors; not only were they amusing, but it definitely helped to lighten the mood in such a dark place.

Puzzles! If you don't like puzzles (including key hunting/fetching), then this campaign probably isn't for you. (Though you should give it a try anyway.) Occasionally, there is another path open/around a puzzle if you really can't figure it out. (Take Map 1, for example.)

Creative environments. The game takes place in an urban/industrial setting. It feels very eerie, something I love to see in L4D campaigns.

Story/plot. You start off at a dock, though you quickly find the army. However, they don't want anything to do with you, so you have to go "the long way around." So yes, there is a story/plot going on, but it isn't necessarily in your face. I get the feeling that there is more stuff going on in the background/outside of the gameplay, and feel like a lot of items/set pieces in the environment hint at something deeper.

Lots of little details to enjoy. Custom weapons! (That are hilarious and awesome- I loved seeing what ridiculous things I could fight with next.)

Re-playability. Different weapon placement, different dialogue, alternative paths, secrets/fun details you may have missed the first time, etc. It's a very immerse campaign- I didn't want to stop playing! I wanted to explore this world more.

Cons:

The environment can be very dark, to the point that it is difficult to see.

It's impossible to do some of the puzzles/jumps with low health. I ended up dying/restarting levels, hoping that the easier routes would be open. (Map 2.)

I ended up stuck in a few spots on the map, but thankfully "teleported" clear of them. The bots, however, weren't very helpful in this regard. They would occasionally just stand there if a Smoker got me, etc. This seems to be a common problem in campaigns, however, so this isn't unique to Kink.

Again, puzzles. They can be quite difficult to solve. If you miss certain jumps, for example, you need to run around and start again or end up dead. For me, this was frustrating but do-able, though I can see why others might get easily annoyed.

Environments/maps, like the puzzles, can be hard to figure out. In map 3 especially, I was pretty confused with I first played. However, with some exploration, you can figure out where you need to go. Again, not really a "con," so to speak, more of a warning to players who would rather rush through/don't like feeling lost.

Conclusion:

The author put a lot of work into Kink, and it shows. I love everything about this campaign. It is unique in story, environment, and gameplay. If you want a different (deeper) L4D2 experience, then you should try this campaign. If you like survival horror, you should try this campaign. It is difficult, but lots of fun. (If you get frustrated while playing, I recommend taking a break and trying again later. Or playing in smaller chunks/one map at a time.)

I really hope that byblo will finish this campaign someday. As is, the non-ending ending made me laugh, but I really want to know what's going on plot-wise. I feel like there is some big secret/finale/interesting twist around the corner (possibly including the army from map 1?) and am really curious as to how it'll all go down.

Thanks for an awesome campaign! I hope to see more work from you in the future! C: