Lack of male character's break the immersion in so many games... and not even only H ones... Lack of diversity also does this: IRL we have women for all tastes, but most games (H or not) have all women in the same busty bimbo standard, and this is gross.
Anyway, I haven't experienced Artificial Academy, but Koikatsu non free mode is bad as hell, in my experience (I hope that I experienced a buggy in that thing, 'cause it was seriously bad). This one is way more enjoyable and natural in the "life simulator" aspect. The sad part is that you are VERY limited on the customization of the girls, and the only one without huge breast were a loli

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Still, I was always curious about that non interactable NPC dressed a little like as Darker than Black's Yin that we could see walking through the corridors some times. I ask myself if she was anything special. Probably not, but it's interesting how a scenario character was better at getting my attention than properly worked on ones, even if for random thing.