Great game, I especially enjoy the fact that small things like sound design are actually done for once, and it's not just the usual 3 tunes (if there is any music at all).
A small thing for feedback is the relationship between Kaira and Amanda, if you do not choose mother/sister specific it gets a bit weird conversations-wise, especially in the early game. I know, in general, the game is designed around... well, depravity, but I was never so much into the incest angle but the landlady/housemate angle is also kind of odd, so I usually go with step-stuff as a compromise.
As a suggestion, maybe add a third option "what is Kaira to Amanda?" so you could, for example, make them mother/daughter, and you are just the stepbro/son. I am not sure how much effort that is, but I would assume adding a third variable is not impossible.
But again, great game.