There are some damn weird people out there, to write this kind of stuff.
In the meantime, some hours later, I've finished Zettai Junshu except for 3 CGs in the last section of the CG library that I couldn't find. (If somebody who has by chance also played it could let me know where to find them, my perfectionist side would be very appreciative of that, but this isn't important enough for me to worry about it.) It was just porn, porn, porn, though (thank god) without weird fetishes. Just about what I expected out of my first nukige.
I really think that after this thread, I severely underestimated how ridiculous VNs could get.