Hallucigenia (ハルキゲニア)

Overview
Hallucigenia (ハルキゲニア) is a fangame by Trendy-Sabamiso, it stars two young girls named Aya (あや) and Aine (あいね). Its current version is 0.008.

Gameplay
You start out playing as Aya in a mostly barren room and access the dream world through a black book on Aya's bed, Aya then takes a different form in the dream world where you can explore. You can unlock Aine later.

Plot
Aya enters her dream world from the black book on her bed. When in the dreamworld you are still Aya, but her appearance differs. It is possible Aya wishes to become this dream Aya.

Additionally, after collecting all effects Aine can be unlocked as a playable character.

Version 0.008
Part1 (Taken from alternative official website)

Part2 (Taken from alternative official website)

Alternative Official Website

Version 0.008 (English)
Translated by HimeNikki

Uboachan Thread

Developer's website