Nice review. Overall I agree with the general sentiment, "The 3 good routes are very high quality for me, but sadly it gets dragged down by 2 subpar routes when you rate the game as a whole ", though personally the first route was really a stand-out for me, overall worth the price alone and a pretty exceptional (love) story on its own and something anyone (Not just BL fans) could enjoy. It felt like the story the author wanted to tell first and foremost, and the rest was mostly... filling the blanks and exploring possibilities. The last route is utter trash that brings the quality of the product down. Even if we can ignore it because by the words of the author it is an AU, it's just an ugly way to end the game and it makes hard to recommend the game for me.
I partiarlly disagree about the ero content though, at least Minakami's one had a fairly good amount of characterization in it with some really good banters that showed off their personalities, which caught me by surprise. I would probably say the same thing about Kawase, though maybe that one would have worked with a fade to black too. But I don't they were badly written as Nasu's mollusks or out of place. The rest is... yeah. They do have characterization in them though, but it felt like they were there because the product is an eroge, especially the one in the last route which was "just why".
Ahah, this is so true.