Okay First off I enjoy the concept it's something others have toyed around with and played with from Rehealer to even a bit of Overwhored. It's a good concept that isn't always done so well however but judging from how "Fleshed out" the "creation" of the first doll was it makes me believe that you aren't gonna follow the steps of other's and half ass this.
For the prologue itself as a opening I do enjoy it though it is indeed very very short and quiet big for what content there is. Is this due to you having so many assets already pumped into this or perhaps a optimization issue?
The art is very well done and I can see what you are going for by making use of the "doll's eyes" when taking control/ giving control back ect ect and I enjoy that.
It makes me wonder though with the fact that you gave so much input on the fact that the Dolls are basically fully customizable with the power given to us, will we actually have some extent of power over how the characters look down the road? Because that would be quiet interesting