Well, I finally got around to playing Gakuen Redux, and I came away with definite mixed feelings. The game was very good and really made me think about what I might do in a situation like that. I also loved G-Type, because it worked for me. Unfortunately, over the course of F-Type I stopped being able to relate to Azasuke. When I play a renai game, I tend to fall into the role of the protagonist, at least in terms of putting myself in their situation, so I loved the redux element of the game. But I just couldn't relate to Azasuke's disconnect problems and his apparent inability to accept that he was now truly a high school student again. Also, given that I haven't grown an inch or gained a pound since the end of my freshman year of high school, I really had a hard time accepting Azasuke's views on physical maturity. That aside, I still enjoyed watching the events of F-Type unfold. When it got to R-Type, well, I admit I mostly lost interest. It was quite clear to me where the story was going to go, and that I wasn't going to like the ending.
The weirdness of the teacher/student thing aside, Ione as heroine didn't work for me at all. I never like older women characters, and Ione was older than Azasuke even in terms of his mental age, so I just couldn't relate.
I just found myself continuing to read just to see how things would play out but without any involvement in the story.
As a side note, I found Azasuke's behavior and ease with which he achieved superiority at his school to be thoroughly unrealistic and distracting. I'm sorry, but there is just no way that a guy who comes across as essentially a loser in the moments we see of his pre-redux life would possess the full range of abilities he claims to have picked up in the ten years after high school, particularly in attracting girls. Especially since we see with his reactions and hesitations that emotionally he hasn't exactly matured much since the first time.
My response seems pretty negative, but I suppose that is in large part because of my dislike for R-Type. Had I written something after G-Type it would have been very positive. I really wondered what was going to happen next. As to the length, I set the game on auto with a setting of 8, so it took however long that would take. Around 7 hours, I think, when you throw in short breaks to grab food or whatever.