I really dig the way shinachiku-castella does corruption, because it is gradual both mentally and physically. Their games begin with sexual harassment and molestation that escalates little by little: verbal assault, butt and boob groping, nipple sucking, kissing neck, foreplay, handjob, titjob etc. This gradual escalation in perverted acts I think this is the main reason why their games have become one of the most popular in the genre.
The issue with some other NTR games is that they advertise "slow corruption" but then the main girl starts having sex from the very first scene (and then it just escalates from there), which in my opinion kills the allure of the gradual physical corruption, even if mentally she's still "resisting" it. Just to give an example,
Promisse Best Left Unkept does exactly this (but otherwise its a pretty decent game).
So I hope that this upcoming game follows the castella winning formula.