It's a game about finding differences.
The system is easy to understand, and if you can find the differences you can smoothly advance through the game.
This is a game where you do n*ght crawling without waking a "tsundere" sister-in-law. As you interfere with your sister-in-law, you can undress, lick (cunt, arse), rub, titty fuck or fingerbang her.
This is a game where you do n*ght crawling without waking up your sister in law. Lick, rub, pluck and insert and finger-bang. ...use a variety a way of touching to conquer your sister-in-law.
The female character had boy friend.You survival with her, let her feel good with you and clear her boyfriend without her knowledge. Then got her! sex with her! let her addicted to sex!