Does this game abide by this forums rules? If the answer is yes, then no further discussion is needed. Considering it has been around for a while the mods have seen, reviewed and approved of it conforming to the set rules.
As for the theme/genre, we see these pointless discussion debating the content on so many threads. Sharing, NTR, Incest, apparent Age of characters, they all spark discussions. But in the end if this forum deems it by their laws (and to extend the laws of the country they are hosting/server located in, then it is deemed allowed.
I live in the Netherlands, and it is true that, as far as i understand, here it is considered illegal if the person (the daughter in this case) is seemingly too young (by appearance considered underage) to be above 18. This is regardless if this is a real life image, or a drawing or a 3d model. All of it is considered illegal.
But as you stated, this site doesn't have to comply with those laws cause its not hosted here. Worst they could do, is ISP block the site if they deem it valid to do so.
With that i end my part in this discussion, and i hope from here on we can get back on topic to discus the game, not the legal aspects anymore.