Kanojo-tachi no Ryuugi is a game made by 130cm back in 2006, during the 'golden age of VN innovation'. Like many of the games made during this period, it is far less bound by convention than you see in modern VNs, which has its ups and downs (as most games from this era do). In this case, the most striking element for modern VN readers would probably be the fact that the protagonist is fully voiced. The second is that, in most of the H-scenes (of which there are plenty), the females are the dominant side and the protagonist isn't a bed yakuza even when he is dominant, for the most part.
Essentially, this game's story begins when Kotaro, the protagonist, is called back to his estranged family's home after his mother dies of illness. There, his twin older sisters, Tobari and Akane are waiting for him... but their attitudes are odd. Akane, the older sister, has become active, mischievous, and selfish, and Tobari, the younger, has become a cold, expressionless young woman. There is no sense that he is welcomed into his old home, despite the fact that he and his sisters were once very close.
Things become a bit clearer when he discovers his sisters are vampires (and bisexual), and he ends up having sexual relations with both of them (Tobari reverse-rape and Akane essentially psychologically cornering him into doing it). Worse, there is no sense of actual affection from either of his sisters, who apparently can draw sustenance from the acts.
Now, the reason why I drew out these initial scenes is because they aren't really spoilers (my rule limiting spoilers to the prologue at max), is because you need to understand that this, typically of most of 130cm's games, is a heavily incestuous story (literally and metaphorically) with some seriously twisted relationships resulting. There is love, but it is often only referenced laterally or after a great deal of pain on all sides. Kotaro has serious hangups that keep him from forming healthy relationships with anyone (mostly because of his weird relations with his sisters, Tobari in particular), and the girls aren't that much better.
Really, it is recommended that Suzuki and Seseri be handled first by most people who read this VN, but I always end up going for Tobari first... mostly because figuring out all that is going on in her head is seriously hard the first time around. Tobari is a genius in general but also a genius when it comes to acting in particular. The drama club and its play, which serve a central role in all the paths to one degree or another, is her idea, as is drawing in Kotaro as the heroine (yes, he does dress up). While there is another club president, she is the obvious leader of the club. Moreover, her forceful personality and overwhelming acting talent pretty much keep anyone else from really even considering disobedience toward her.
Her relationship with Kotaro, in their childhood, was that of really close siblings, but the changes she began to experience (vampires in this setting are atavistic throwbacks to previous generations who lose the ability to have children, live eternally, and must consume blood or life energy through sexual intercourse in order to survive) shattered their family without Kotaro every knowing why.
Her attitude toward Kotaro is cold and distant, except when she suddenly draws him into sexual relations or the drama club in general. She loves Akane and will show emotion toward her easily, but in most other matters, her expression remains flat. Her path is a journey of unwinding the twisted ball of yarn that is her emotions toward Kotaro and the circumstances that make everything about their relationship difficult.
Akane is technically the older sister, but at first glance, you would guess her to be the younger. She is more active, she is less mature, and she has no intention of controlling any of her impulses. Anything that feels good (drinking blood, having sex with Kotaro, eating food, etc) is good for her, and she has no interest in struggling to do anything she doesn't feel like doing.
As a child, Akane was sickly to the extreme, rarely leaving her bed and unable to do even the simplest of activities for the most part. For her, vampirism was salvation, though it cost her five years with her younger brother (she does care, but her hedonistic nature dominates mostly). While she isn't precisely affectionate toward Kotaro (there is some affection, but, again, her hedonism tends to hide it), she is affectionate and loving toward Tobari. Despite this, Tobari can be considered to be the 'dependent twin' of the two.
Akane's path is more about dealing with Akane's own inability to understand certain aspects of her sister's feelings toward Kotaro, the harmful aspects of her impulsiveness, and Kotaro himself. It is more straightforward than Tobari's path, but it also has some serious issues, some of them leftover from before she became a vampire.
Suzuki is a misanthrope who only trusts Seseri. She is described as 'excruciatingly beautiful', but her manner, especially toward Kotaro, tends toward the acidic in the best of times. She has a rather extreme version of the aversion many women of her age have for sexuality in general, though it does have a good reason.
Her path is more about Kotaro getting past his siscon and her getting past her dislike of him (and herself) than anything else. Of the heroines, she is by far the most psychologically fragile, despite her thorny persona. She understands Kotaro the best of the heroines, when it comes down to it on a fundamental level, and this becomes rather evident toward the conclusion of the path.
There is no real romance in this path, despite them forming a sexual, even intimate relationship. This is because Suzuki is fundamentally incapable of romantic feelings, though she gets to the point where she feels all right around Kotaro.
Seseri is your standard deredere kouhai and Suzuki's best friend. Seseri is a really straightforward and innocent girl who hits everything head on, yet she is also sensitive enough to get down in the dumps at times, though she usually gets right back up. The very first scene of the game has her confessing her love to Kotaro and him refusing her.
Her path on the surface seems to be an odd couple romance, but in fact it is a bit different. Seseri's feelings toward Kotaro never change, she loves him and she is really open about this fact.
However, Kotaro never forms romantic feelings toward her, in the classic sense. Instead, he becomes dependent on her warm presence in his life. This is an oddly touching ending, but at the same time it follows the pattern of Suzuki's, where one side is in love and the other side is with them for reasons other than love.
Honoka's path splits off pretty late from Akane's path, before things get all twisted up with Tobari and requires that you have played Akane's path to pursue. Honoka is the retainer (not maid) for the Shirogane family (Tobari and Akane) and a sort of blood bag for the two vampires. On the surface she is a mature older woman, but underneath she is pretty girly.
Her path is the most straightforward romance in the game, with an incident bringing her feelings for Kotaro into the open and forcing her to confront them. She has some real-life hangups that make for some mild drama toward the end, but her path ends on a pretty familiar (for charage readers) note.
Chisato is the game's tsundere osananajimi, and she is also perhaps the most template of the heroines. For this reason alone, I would have wanted to avoid her path, but since I'd already gone through all the other paths, I felt I had to finish hers as well. This is perhaps the only path in the game where the protagonist's past is revealed in something other than the words of the protagonist and heroines. There are a few flashback scenes that are pretty revealing about a young Tobari and Chisato, and it does add to the story in general... but it also felt like the writer was favoring the least interesting heroine in the game a bit excessively.
Like all the heroines except Seseri, she has issues. Chisato has an inferiority complex toward Tobari, whom she considers a friend (Kotaro also has one toward Tobari), and she is by nature a hard worker who makes up for a lack of talent by putting more effort and time into things. The path is pretty revealing about Tobari as well... however, it feels like Tobari's path should have been the one route-locked, not Chisato's, in the end.
There is no need to hide this, but this is the game's true ending. This ending serves as an alternate ending to Tobari's path and is fairly dramatic. To be honest, I found this about ten times more interesting than most of the other paths in this game, save for Tobari's original one... which is probably the point. the first half of this path is the Tobari path told entirely from Tobari's point of view up until a certain turning point, where Kotaro takes an action that is different from the original.
This game has a number of flaws, not the least of which that there really only needed to be three heroines (Honoka, Tobari, and Akane) and the fact that the actual paths feel abrupt at points, showing the peculiarly odd pacing that was common to a lot of games from the time. However, it is also a nice game for people who like messed up and twisted relationships that don't stray into NTR or rape-related stuff.