I think Mity mentioned that there would be a fifth part that would tie up all the loose ends and give a proper ending. It starts with the player being dragged out of his apartment and across time, so maybe back in the apartment at present day as an avatar? Also, would be nice to get all of the girls back for a harem or at least an orgy. They also still need to finish the snake sisters plot and the mystery of Shady. Shady might be the player sent back into the past to help himself? Perhaps a tie in into Mitys next game? In any case, we need all of the girls back for one last fuck.