It took me a day to unlock Kendo's 1.2 ending "Embracing Betrayal"
The first step is for Satoshi and Shizuk to talk at night. Don’t talk on the 3rd night
, otherwise it will go directly to the 1.1 ending "The King and His Cheating Queen",
Satoshi and Shizuk talked at night until the second night,
and went to the beach to talk to Mary in the morning. Select [I love you] [I want a future with you] to enter ending 1,
Kendo and Mari’s secret room sex options [Do it...].
After Kendo and Mary Hot Spring sex options [Yes...],
and then selecting [Please... let me watch...] and [Yes,i *really*mean it] at the beach You will enter the ending of 1.2 "Embracing Betrayal"
I would recommend unlocking the 1.2 ending first and then unlocking the 1.1 ending so there won't be any conflicts.