/jp/ - Otaku Culture

Has anyone here read Kansen series?

Not exactly my thing in terms of plot, otherwise I'd give it a try.
But I kinda like Sasaki's art and some fetishes included in this series.
So after browsing through CG galleries I noticed how first three games are mostly bad ends with rape/gangrape.
Then 4 started introducing more (what I assume are) post bad end scenes featuring infected heroines fucking MC and participating in gangbangs.
Then 5 introduced even more content like that.
And then BB is basically all about multiple infected girls fucking MC and less gangbangs.

I'm curious, were they just testing different approaches for each game?
Or is it what readers ultimately wanted to see more of?