The After Story's ending was saving the story as a whole but nothing is hot. The problem is that I don't buy she fell for him mentally but even if that was the case, the voice actress' annoyingly high-pitched, cliché hentai screaming doesn't seem pleasureful at all and the lack of CG surely doesn't help. The story became kind of interesting near the end, when MC acted intelligently by kind of accepting she enjoys it. That's it, though.
This would be hundred times better if the characters had less feelings or if it didn't mean the end of the world due to what's happening to them. If MC himself comes across such an idea without a fetish, you better make sure to either be a god-tier writer or simply put more effort into hot sex scenes next time. The conquering required phantasy to be enjoyed because it was repetitive, predictable and boring.