After reading some of the negative feedback, I had to play it for myself - and I have to say it's a totally fine, serviceable game. I don't read NTR much (so I don't have enough experience to say if this qualifies as NTR or a subgenre), but I don't mind it either.
Honestly I don't know how you could interpret the player character as a "loser"; he managed to make an impression on a girl who's slept with hundreds of other guys. In some games you date the girl, and in some you just swing with them (kinda like real life!) - so I don't understand all the hate.