finished one route for now (the confrontation one). Gotta agree that Natsuko's fall is WAY too fast to the point everything after the first sex is just her boosting the speed rather than Kazuya forcing her too. There's no torturing (like orgasm denial for 3 days in Kedamono Ie) it's just full blown pervert women losing all her logical thinking with kisses.
The route is depressing but at least the ending is hopeful.