Venus Blood Hypno is by far my favorite Venus Blood game. There are a number of obvious reasons. The story itself is the deepest and most interesting, it is emotionally powerful, and, if you follow the Law route, it is possible to avoid sexual corruption issues entirely.
However, the true reason I love this game is because of Leonhardt and Anora.
Leonhardt and Anora have one of the most powerful, deepest relationships I've seen in any type of VN, ever. The emotional bonds between them are literally inseparable, and the trust between them is literally unbreakable. They have had innumerable horrible experiences, which have left them bitter and cynical, but their love for one another, while having a strong element of mutual dependence, is nonetheless untainted. It is unselfish and giving, and, while no sane person would ever envy them their lives, it is hard not to envy their love.
Leonhardt and Anora were once members of the Arknoa royal family, a human (sort-of) kingdom that lay at the lowest level of Helvetica, tasked with protecting the seal on the demonic races, but considered to be tainted and cursed because of the unique abilities the family often displayed. Anora, because her abilities were particularly strong, was feared and generally distanced from most of the family. Only her older cousin, Leonhardt, was close to her from the beginning, and when the seal broke and the demons flowed forth, it was Leon who carried her as he sought to escape certain death. Unfortunately for them both, Calvia Karlsefni, the Demon Empress who destroyed their family, was waiting... and in exchange for Leonhardt begging shamelessly for their lives, she made them her toys.
Leonhardt and Anora were used in an experimental procedure to create a weapon to get around the weakness of demons to divine power, fusing a different soul into that of another living being, transforming them into something that was neither human nor demon. Of all those who underwent the procedure, less than one in ten thousand survived, and many of those went insane or burned out soon after. They became what is referred to in the story as a 'Reisu Unit' (which refers to the fact that they use the soul fused to them and their own soul as fuel for their power). Incidentally, none of this is spoiler, really.
Now, down to the setting, one of the other reasons I love this game. Hypno's setting is dark, even for a Venus Blood game, where tentacles about and most of the main characters have demonic blood. In the events leading up to the game's beginning, the demons, who had long been confined to an underground world where there wasn't enough energy to sustain them, much less keep them powerful, overcame this problem in a way that was both simple and terrible... they used a new technology (called Laugraphia) to transform people's souls into crystals called Tactica, that could be used to power their magic, thus allowing them to break the seals and emerge back into the surface.
The demons went to war with the forces of angels and humans led by the Goddess, and the Great War began. Using the Reisu Units, the demons forced open the teleportation gates to the floating continent from the other surrounding continents, and Calvia killed the Goddess, transforming her into a Tactica.
Now, the Empire, which is the most powerful of the four demonic nations, rules the central floating continent and the southern continent of Brookheart. It converts large numbers of humans to Tactica on a daily basis, using any excuse such as criminality, religious activity, or simply being in the wrong place at the right time. All four nations are reliant on Tactica technology, at least partially because they are all afraid to give it up, lest the others rush in and overwhelm them using that power. As a point of reference, each of the four demon lords possesses at least one Myorne Class Tactica, which is a Tactica containing the equivalent of more than a million souls. It is common for most mid and high level commanders to possess a Ten-thousand soul Tactica, and most soldiers with potential have one that contains a hundred or more. Worse, Tactica can be 'used up' if their power is abused, meaning that huge numbers of souls are being burned like fuel on a fire on a daily basis.
As a setting, it has both depth and darkness, two things that I can't help but like.
Hypno, like most games in the series, is split between Law and Chaos paths, but with a slightly different twist, there is a true Law ending that can only be accessed under specific conditions on a third playthrough after you've been through the Law and Chaos paths once each. This is the True Law Anora ending, and it is, quite obviously, the single best (or at least the happiest) of the game's endings. I cried, lol.