from what i got from the source and comparations: the story of this one amost remain the same with the exception of been a little more light than the eroge and the other guy is only present on the 1st minutes and then "dissapear", omit some of the things , and the brother is less of an asshole and more of pervert only (even the bathroom scene is completly diferent for good)
Still don't like is a semi-NTR in part ... but i must admit she looks even better here ♥