I think Lilith's Throne is considered open world, there is a big world and tons of people to do and things to see but its not a 3d game so some might be dissuaded. Personally its my fav porn game of all time
Basically in this game you go to a job to get agility points and money, the agility points allow you to get better jobs and thus better agility points and money. The sex aspect is only if you either fail a job and you can touch the portrait in order to get sex or if you go to the gym and you can...