It's exclusivity in subject matter is not its biggest enemy, but its potentials as an adaptation instead. It's a great adaptation, undoubtedly done by a fan of the original novel. However, it's 2 chapters short (these stories are extremely difficult to adapt anyway), which is a shame, and a lot of the discursive elements, like internal monologues, were replaced with visual presentations, despite the fact that to me, the discursive parts of Goth is what made it not limited to just a gory horror p**n. So if you were to choose either the manga or the novel, I would still recommend the original novel first even if you're more of a fan of manga. The twists also felt more satisfying in the original novel, not to mention that there are 2 whole more stories to read, which were excellent and easily the best ones.
Still, the stories are closely adapted and did justice to the original work, and are entertaining to read. The art is clear, concise, and beautiful, and the visual design is an excellent adaptation of Goth's tone and subject matter. A solid addition to your manga shelf.
This might sound like a spoiler, but from the first page of the manga you'll learn that your male lead isn't a "normal person" anyway, which is why I felt like those internal monologues in the novel were important. The point of Goth, I guess, is what's so different between the male lead and the antagonists; either that, or the point was to get in the heads of these psychos and know them a little better. Either way, the novel goes a little harder into that. Don't get me wrong though, the manga is still great.
