Essensially, this manga is for those who love gore, extreme nudility, and horror. If you can't take any of these things, stay away from this manga at all costs or you will have wierd images burned into your brain.
Story (6/10): I'll be honest, the plot isn't great. Once you get into it (around 25 chapters in) the story begins to get really repetitive. Outside of deadtube videos and events, the story of the characters in school (without the gore) is seriously medicore. Even Tomohiro Machiya's main goal in deadtube is really not written well (not explaining the goal due to spoilers but yeah). There are a few inconsistencies and questional points in the plot (again not going into details due to spoilers). However besides this cases, the story of the deadtube videos and events are made reasonably well. There are plenty of plot twists in that make you appreciate the author's creativity (or what seems to be mental insanity to some). Overall, the story wasn't great, but it wasn't exactly bad either.
Art (10/10): The art is simply amazing. The art is clearly refined down to the detail and the art quality is really consistent throughout the all of the chapters. The extreme gore and death scenes are all done flawlessly with extreme precision. The art does a great job of displaying the character's emotions such as pleasure, insanity, questional mental states, and anger. The quality of art is so good that it makes me question Kitakawa Touta's sanity. If you can stomach all the gore, I would honestly recommend reading this just for the art.
Character (5/10): The character development wasn't great either. The characters are really only developed through deadtube and gory events. Although the character's fetish's, insanity, and enjoyments where very well characterized, everything else about the character was practically ignored. Thus, I gave the characters a really average score.
Enjoyment (5/10): I believe the amount of enjoyment for each person will vary drastically due to the differences in taste. Personally as someone who doesn't love extreme gore and death, naturally a manga such as this wouldn't give me much enjoyment. My enjoyment mainly came from the amazing art and some interesting plot twists through the story. However, if you're someone who love gore and messed up scenes, this manga would become your favorite very fast.
Overall (8/10): Although my enjoyment wasn't very high, I still have to give it to this manga for the fantastic art and beautifully constructed scenes of mental insanity. The overall high score largely came from the extremely accurate descriptions of messed up sh*t through the flawless art. This manga is most definitely the most messed up manga of everything I've seen.
TLDR - Like gore? Read it. Don't like gore? Don't read it. Indifferent? Read it cuz art is cool.