Its possible to have sex with two (out of 3), for one you need to have won the basket test, for the other I dont remind any specific, go with the flow (two events/scene related to going on dates).
Not sure how the roof area events are set, it was possible to have sex then, locked back as if its no longer an option ? (Do those girls have period ?
).
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As to how long the game has been in development until now, be careful, as there is no way to know how exactly one life actually is/had been. What matter = either progress or at last contact being kept, since it make the option of another update more tangible.
In any case, the game is very early on all accounts, as it is, if a quarter of the story is there I would be correct, while Ill go for quite a lengthy (and depth) gameplay given some of the "yet" ingame features (the girls gallery, the way relations are handled. As to features, its possible to find>Acquire support (the girl from the cemetery would be the second (after your first maid, then, depend who get updated first (there is also the big girl from the Servant guild with her Million price tag), the doctor and more later on (did good to launch and play some more, met one of the three (?) at home on returning, was introduced by my maid to the club (available at night). Had the health checkup (introduction to the doctor)
.
Then, the open path as to make the three (or more possibly) of the actual related girls (being born from with part of blood related to the PC, family type of setting there, even if it could be quite interesting to see given how long ago the actual "link" had actually been made (this as it is explained (partially) that the Master are all from the same family (as if there is a reason, its yet unknown.
By the way, one of these is a incest fan, related to a at last 1/8 to the PC.
As it is and given how humans are in reality (who would give full course (money + control) to someone unproven ?) guess all is quite fitting as it is.
All considered, its early, has already some content, a very large area of future development (which is quite the best part it is not ?). So, to be seen with hope it will long until the game reach completion..