This is Genshiken. But, at the same time, it's not.
Genshiken. An anime-series we consider as funny and disturbing (Mostly due to Madarame's comments), but still a spot-on image of what a real otaku is like. In this book, however, none of those elements are present. Instead, we get a very serious take on the Genshiken series, with many creepypasta-like scares and supernatural happenings throughout the book.
The story is basicly about a doujin-soft named "Kyodai*Kenka", a doujin game known for including a real-life murder if you beat it in a specific order. At least that's the rumor. Kuchiki's trying to play this game, but dissappears. Meanwhile,
a person named "Ranto Hairu" becomes Shiiou University's chairman, with a goal to destroy everything indecent in the clubs on campus. And so it begins...
While the novel does great by capturing every character's personality and traits, it has very little to do with Genshiken. About 2/3 of the book is about the main antagonist, Ranto Hairu, and his henchman , Igarashi. The novel has taken a very strange turn, mystery, and the Anime/Manga related themes are absent, something Genshiken was famous for having lots of. I will praise it for including drawing made by the original mangaka and for going deeper into the relationship of Madarame and Kasukabe and I must also admit that the ending was great, even though the rest of the book was just "fine". But was it realistic? Not at all.
The story left many plotholes when it hit its conclusion, but it's still a "fine" story nevertheless. It may be more serious than Genshiken, more mystery-orientated and most of all, scary, but it's still great to be able to read further about the Genshiken guys. If anything, I would categorize this story as "horror", which you will understand if you read it.
If you enjoy mystery/horror or are a hard-core Genshiken fan (like me), you will most likely enjoy this or find it "okay". If you wanted a novel like the TV-series or Manga, this is not the place to find it.