One more chapter to go until I can buy it!
One week and one chapter to go, you mean
You could think of it as a weird preorder perk, where you get the game a fifth at a time starting five months before non-preorderers get it.
I think it is, all five parts together, easily going to be worth the price, based on the first 3/5ths. I'm not so sure about if you were to buy only a single episode at the $10 price amazon is asking, though.