Just wanted to say that your game is thrilling, you did a great job with the writing. My only complaint is the achievements are very strong and make the game quite easy.
I know you're done with it but if you ever wanted to revisit it and add some content, you could add a random chance each night that your sisters friend is staying over and give the option to fool around with them as well. Or maybe another family member is visiting and staying in your sisters room with her. They could have their own stats. Could just be a surprise chance visit, or even lead to different endings.
Additionally there could be a random chance each night that she's awake and doing something sexual and give the player the chance to peek and risk getting caught.
Just some ideas bouncing around in my head. But overall 10/10.