"EtlanZ" on the back cover is a group credit for multiple people:
EKUSU:
original music; arrangement with Riz
Riz:
arranged BGM and minigame music
hydden:
arranged 2.19 only
Also, INSIDE SYSTEM refers to the first game in the logo in English as DARK WITCH'S STORY, but that doesn't seem to be present in any of the material for this game.