I will agree with some of the reviews, that this is more like a movie, than a game. And this game gets negative reviews because people are expecting a game, not a movie. But if it was something like "Wolf Among Us" ("The Walking Dead" is a bit off, since it's not a detective story), no one would have complained, I think. And if there were more choices, that influence the game, if collectibles did not only tell you some background, but also influenced the ending somehow, if saving ghosts influenced the story... There are a lot of ifs, that could have been covered if this was an episodic game and if it did not feel like pieces were cut off of it. And if it actually had a map IN the game, not on a web-page.
But if you forget about all these, it's not a bad story. Yes, if the background told by the collectibles were more integrated in the main story, characters could become more... Real. Less flat. But overall, I actually enjoyed it. It has good dynamic: not too fast (since it's not an action game), but not too slow (as some detective quests can be), it has motivation, it has mystery.
I think I'll give it 7/10. Maybe 7.5/10, since it kinda reminded me of Dreamfall (although Dreamfall had more gameplay). I wonder if Airtight Games can make something in similar fashion, while covering some negative points. Or they can simply try an approach closer to Telltale Games, I guess.