This is a tyranobuider sim where the MC with a NTR fetish takes his GF to get fucked at a male brothel, and it's a fairly typical NTS->NTR for most routes.
TBH I'm not sure. The engine is so ass that it doesn't even have a skip feature, and it's a bit obtuse how to trigger flags and unlocks. I got one or two and then just went and dug into the files.
The gallery got reclassified from a gamecg to doujinshi. How come? Does this not count as a game for some reason?
first of all the game comes with a walkthrough that explains how to get endings
the normal ending is just where you don't unlock any other ending and stays NTS each guy she can have sex with has their own ending which is basically after MC takes things to the extreme, i only did one but it wasn't exactly NTR then the special ending is basically a true love end
tyrano builder is a crappy engine but it can support text skip so that's on the game dev
and this got reclassified because someone is an idiot, i don't know how to fix that, maybe try complaining on the forum
also you should have linked to the game instead of the cien, or both at least https://www.dlsite.com/maniax/work/=/product_id/RJ01299768.html
The dlsite page doesn't load for me in Europe. Not sure why, usually I can load pages just fine, so I assumed it was broken. Cien seemed like the most official source I could find.
you can thank visa and mastercard for that. a while back they went after dlsite, blocking payments through them and eventually dlsite got them to accept payments again by blocking certain "problematic content" from foreigners. this games dev mentions an issue related to this in a post from the very cien you linked. you can still view the page with a japanese IP though and the RJ code is still useful even if you can't since there are sites that scrape data from dlsite that aren't blocked