The introduction was awesome imo - there's a lot of stuff that hints on what's going to happen, and builds up well. I loved the First Impact moment too, suddenly while it's all fun and games, they start getting noticed by everyone.
HOWEVER, that Second Impact was a bad choice imo. I mean, all of a sudden, the neo-human girls become sexually insatiable? This is kinda what the dev did with his other game focused on Anna. This sudden and extreme change makes the whole feel of the game really boring in my opinion.
And then there's the contract. So the old men can write a name, just the name, and that neo-human female is now their sexual toy. So we don't just get the female having an extreme sexual appetite (see Anna's Second Impact, where she can't even think straight and goes to fuck the first random guy, even though her boyfriend is coming back soon), but also that she can't escape the male that chose her, even if she could think straight.
This puts them in a position of inescapable demise. There's no longer a point in reading on, as you already know what's going to happen. In this situation there's no need for inner monologues or even thoughts of guilt, even though they do occur in some cases, as it's clear they do enjoy what's happening a lot plus what's happening is not even their choice to begin with.
What's interesting in this type of games to me is to see how this all happened, from a point of it being impossible, to a point of it being natural. The "journey" so to say, rather than the destination. In this case (and other cases like this) though, this happens because "let's just skip all that and say it just happens".
No judging if that's your thing, but it's definitely not mine.
. First half of the game is good, second half just plain bad 
