Great work. Best game I have ever seen ;) You might have this planned already. During the shower scene, there is 2x the option to endure. Right now it does nothing I am aware of. It should during blowjob trigger her to try harder or start sucking you. It should during sex cause her to come, when you endure long enough (5-10 times). There sould be progression in her answers, right now it seems as if smth. would happen, but her answers just loop.
Also during night, facial expressions, and reactions could be expanded imho. Give her dialogue, when she is awake pls. Option to hide under blanket if Kan comes, and try to make her come when he watches (and if she is awake, might respond to him like Can:"you good"her:"yes, you can leave""you sure, youre face is red?""y-yes please leave now *orgasms*", also will try to endure and complain later in cute fashion..). I hope you can eventually do more to her friend too. Make her watch, what you do to her. Also have them both in the same window would be cool -> make them sleep in same bed?
Just some thoughts. Cheers.