The best part of this game is that it ISN'T just NTR. There are several routes and scenes that keep the heroine faithful, so the NTR isn't forced onto the player, it's a choice they make.
I believe that this is what makes an NTR game truly good, it having just as much NTR as any other NTR game (as in, the NTR isn't sidelined in favor of other content) but also having plenty of good non-NTR content.
I think this is developer intent too, because it is initially pure netorase, and only evolves into cheating netorare if you let it get that far.