A Couple’s Duet of Love & Lust

In this game, you make the decisions as both the male and female protagonists, affecting the plot in a realistic, organic, and complex manner.
The storyline adapts according to the developing personality traits of the two main characters, and there are no clear-cut paths to the many and different storylines you could follow.
You can challenge yourself to steer the couple towards a path that strengthens their love and overcome the challenges as either a conventional couple or a more adventurous one.
Or you can choose to push them down the path of ruin and debauchery. It's all up to your decision, but reaching the end you want will be a challenge and a game itself.

The game on 3DCG with some processing, takes a little getting used to. The version on Ren'py is declared for Win and Linux, plus an android file - download what you need.

As for the passage - in the main menu there is an item - Guides/Help c shorter human passage - a set of consecutive answers or choices,
that you need to do to pass the game one way or another. Plus there's a pdf in the folder - but it's a giant flowchart, its a challenge to watch and a game itself,
as written above; one person I remember writing that he lacked a bachelor's degree in chemistry to figure out what's what in there... They're not for the latest version, but still.