Played this a while ago, will look into this version, and see if there is anything changed so far. It sounds interesting, but for me it was not so good at all.
You and your BFF (haha) and your GF, your sister and the school-slut (somehow) will have to pair up to search the mansion. The first decision "who goes with whom" will define how the sexual relationships will go.
First thing: Gender change is something I always dislike (playing as girl, okay) so to stay in character (which means I want to be a man again, and no I don't want to suck every dick now, because I suddenly was transformed into a girl) will trigger the NTR-path. Because if YOU won't take the dick, someone other has to do it...which will be in most places your GF/sister/slut.
Second: The scenes are written nicely, the story okay, my biggest problem is the way they let the characters get corrupted. You will get yourself/GF/sister/slut getting bombofied in the first rooms, and from then on, every time you will see some sexual outcome, which is sometimes interesting, most times somehow unlogical...
Third: The ends I have seen didn't gave me some pleasant feelings, but at least this game is finished, and has endings.