So I see mention of a "secret area" that got added, but not where it is or exactly how to access it...
Also, there's a version 2.2 out, apparently.
Dlsite update note did not mentioned it and I cannon find that version either, probably some kind of mistake.
Clear the game once, then to access the secret area right click or x at start menu then followed the crow.
*Should you lose sight of purple hair girl, go to the other side of the map.*
First scene go inside main building, left then followed.
Second scene go inside main building, right then followed.
Third scene blue hair kunoichi from first scene go left instead then followed.
Third scene blue hat girl from blue hair kunoichi scene followed the road that leads to the hut hidden passage then followed.
Third scene black hair miko go inside main building, right right up then followed.
Ending room followed the road that leads to the hut hidden passage, go back through the hidden passage into the main building, then followed and wait for her to came out from hidden passage, followed her again for ending CG