As someone who likes this genre, I can say with confidence that Doubt was, by far, one of the most disappointing, pathetically thrown together anime OR manga I've picked up so far.
Reading this manga, I was completely appalled with how much of a train wreck this was. At first glance, this seems like an interesting story concept, and it is. I've read and seen my fair share in the "survival game" genre, and this is an awesome story concept with a lot of potential, which got me interested to begin with. That's why it's so easy to see where Doubt totally blew it.
Story (1/10 - Pathetic): The worst part of this entire manga. Straight from the beginning, we are thrown into the pre-game setup. All of the characters are meeting together with little context given. There is no "main character is living a normal life sitting at the back of the classroom when something out of the ordinary happens" scenario. The characters all come together saying "I got this weird message, haha" and that's pretty much it for the exposition. We're given typical manga tropes as characters, which is to be expected, but really doesn't help Doubt's case, proving that they stuck with just the bare minimum. We're even given a MC with absolutely no personality or outstanding qualities.
The pre-game development was extremely weak to say the least. They're thrown into the game when we still know very little about the characters or what's going on. From there, the story continues without any buildup or a sense of major mystery, and the story proceeds to rush itself into a complete mess. Again, no development, no tension, no nothing. The characters don't even seem to be afraid about their friends being murdered and being in a bloody dark hell hole. This even furthers the reader from connecting to the characters in any possible way.
However, maybe the worst part of the story is how predictable it is. The mystery pretty much gave itself away, and I could predict the ending before the end of volume one. Obviously this led to a dull, anticlimactic ending that anyone could see coming. You would not believe how obvious and unimaginative this story came out to be. No redeeming qualities.
Art (6/10 - Fair): There isn't much to talk about here. They made some scenes pretty spooky, lots of blood, characters are drawn in a typical way, but not bad. So what? In Doubt's case, the art is not enough to save it from being complete hell. In fact, one of the reasons so many enjoyed this is probably because of the eerie art that was used as a crutch for a such terrible story. Art is hardly worth recognizing and would not redeem this thing in a million years. Moving on.
Character (2/10 - Dreadful): Characters get virtually no development or backstories. There is no investment in any of the characters and character deaths are needlessly thrown around to compensate for a lacking mystery. Character deaths are also sloppy and anticlimactic to the point that I actually wish there were more characters, because when only a few characters are suddenly left, the story gets even more boring. Completely disappointing and a huge waste of potential... potential. Yeah, potential potential.
Enjoyment (2/10 - Dreadful): Needless to say, when the ending and "plot twists" are obvious, with the characters being one dimensional, and with a story with no development or mystery, there isn't much to enjoy. There were a few moments of suspense that were sort of creepy. That's basically the only thing that saves the "enjoyment" from a 1/10. Believe me, I would have dropped this thing if it wasn't a measly four volumes.
Overall (2/10 - Dreadful): All things considered, I think a 2/10 is fair if not generous. I'm sure they could have found ways to make it even worse, like maybe if they found it in an old scrapbook titled "Baby's First Manga", so I'll spare it from the 1/10 rating.
Doubt is a horrendous attempt at a potentially engaging and mysterious story. I'm hoping I don't get a ton of "Not Helpful"s for such a low score, but I'm telling you, this thing was painful to read. Having zero development, character depth, and tension was really killing me. A cool concept that was completely thrown away by a rather pathetic execution.
TL;DR: Just... don't bother.
