Well I'm one of the ones who played the game through from Chapter 1 - 4 as one complete game.
Therefore, I don't judge the game chapter at a time but rather the whole game as a complete entity and I thoroughly enjoyed the game.
In my opinion the chapters are not stand alone and therefore should not be rated separately.
It's rather like judging Jack without Jill, or Laurel without Hardy.
That said my opinion of the game, as a whole, is that it deserves probably a B or B+.
I believe that flotsam did mention something similar in this review.
You laugh because I'm different
I laugh because you're all the same
Of all the things I've lost, I miss my mind the most.