This is a partial remake/rewrite of Sengoku Koihime, which was released back in 2013. It is by Baseson, the makers of the Koihime Musou series, and the protagonist is the nephew of the protagonist from that series. It is based on the Moeshouden fandisc ending (where the Shin Koihime Musou heroines are all together). In addition to h-scenes, the text itself has been partially rewritten (it is more noticeable later in the game), and they added on the Houjou Chapters, a ten-hour after story.
The story begins at the battle of Dengaku Hazama (the point where about ninety percent of all Sengoku Jidai-based historical fiction begin), where Oda Nobunaga, the lord of Owari, ambushes and kills the Imagawa Yoshimoto, who was considered to be one of the greatest lords of Japan at the time. The protagonist is pulled from his own (modern) world and arrives there in a ball of light, where he is taken in by the female version of Nobunaga (Kuon).
Unlike the Koihime Musou series, there is no battle system involved here, which is great, considering that the story of this thing alone is about 1.5 times the size of Shin Koihime Musou, which was twice as long as the original Koihime Musou. In other words, this is probably the longest kinetic VN in existence, right now, easily surpassing ChuSinGura and leaving works like Grisaia in the dust as far as sheer size goes. This has its upsides and downsides... but it does manage to develop the heroines to a decent level, if at the cost of a certain degree of fatigue on my part.
In terms of structure, this VN is actually a bit closer to the original Koihime Musou, in that there is only one path and all the heroines from the various clans end up with the protagonist. There are five major arcs... first is the Owari and Mino chapters, where the protagonist earns the trust of the Oda clan and begins to build his own unit. The second is the Kyouto/Oumi/Echizen chapters, whose ending is the midgame turning point. The third one is the Echigo chapters, where the protagonist gets involved with Kagetora (Miku) and her clan. The fourth is the Takeda arc, where the protagonist gets involved with the equivalent of Takeda Shingen (Hikari), who was considered one of the best strategists of the era. The fifth and final arc of the main story is the violent conclusion to the battle with the oni. The Houjou arc, which is an after-story, I count separately since the main conflict of the original story is over before it starts.
In terms of raw narrative quality... this VN is top-level. Baseson has a lot of talent available, and this VN shows it off to best advantage. The writing is detailed and gripping, the dialog generally interesting and/or dramatic, and the VN as a whole is well-paces for something so long and drawn out.
If I have a complaint, it is that they didn't voice the protagonist... considering how completely central to the story he is, there really was no reason not to do so, considering the sheer amount of money they have to have spent on this thing in the first place, lol. In terms of raw numbers, there are also a massive number of h-scenes, but they don't dominate things, for the most part (main heroines generally get two or three, with sub-heroines getting one for the most part). This is inevitable, as there are something like thirty heroines in all, making for a rather massive cast, lol.
One huge difficulty at least some readers will experience is the sheer amount of historical background knowledge this VN demands of the reader. For someone born in Japan, it is all learned as a matter of course by the end of middle school, but for those of us on this side of the puddle, it takes research to really grasp a lot of what is going on. In particular, things like the Southern Court and the Onin War aren't generally given much attention in most anime or VNs based in the era, so even if you've played other games or read other stories based in the same era, you might not be able to grasp what is going on fully.
Another issue is that the traditional roles of the Imperial Court and the Bakufu (whichever Bakufu that is) are things non-Japanese will have trouble grasping. The role of the Imperial Court after the Heian era ended is very much symbolic, cultural, and religious rather than political, though it is used as a political tool by each incarnation of the Bakufu (Shogunate). The duality of the reverence held for the Imperial line and the disregard (though it isn't presented as such) for them in political matters is a bit hard for Westerners to grasp... it took me a while, too.
The second huge difficulty is... the sheer amount of archaic language involved. A lot of terms that went out of use in common Japanese decades ago are common throughout this VN, and I can guarantee that even people who are able to follow Dies Irae might have trouble with this VN at times due to this. In particular, the political terms of the era can be difficult to grasp and actually require some research to fully understand, as their translation doesn't really get across their actual nature without a lot of context.
My conclusion? If you liked Shin Koihime Musou, you'll probably love this VN, though it is quite a bit darker and more visceral at times. The sheer length of this VN means you'll probably suffer from fatigue long before you finish it, so I recommend taking it in smaller doses (finish one of the major arcs, then take a day off, for example), as it takes a while to process all the information involved at times. The addition of the Houjou arc, which is about equal in length to the Echigo arc, is a huge plus for the VN, but finishing this thing has left me pretty exhausted, hahaha.