DLsite: https://www.dlsite.com/maniax/work/=/product_id/RJ01292275.html

Looks like there isn't an actual order to this thing: most girls got their own folder in the original archive one downloads upon purchase… Yeah, this is why the introduction portion repeats a lot. For my own peace of mind, I'll list all folders and where the pics are supposed to go.

※おまけ (What follows is inside this folder)

双生 -> 001

一週目 (What follows is inside this folder)

吸血 -> 002

家畜 -> 003

山 -> 右を選択する -> 004
山 -> 左を選択する -> 005

森 -> 006

沼 -> 007

洞窟 -> 008

海 -> 009

空 -> 010

粘液 -> 011

二週目 (What follows is inside this folder)

アスカを選ぶ -> 012

バットエンド -> 013

ミリアを選ぶ -> 014

モダリアを選ぶ -> 015