Doubt is a very generic survival horror manga. It involves a few characters who don't know each other very well, quickly jumping into cliches from horror movies.

It isn't very dramatic as most characters are killed off screen and with little evidence pointing to the real culprit. Therefore, since the characters aren't trying to solve the mistery like the reader likely would want, it doesn't seem to have a plot.

While it is also made to look like a guessing game (kind of like psychological horror), most of the actions don't contribute to this feeling. Certain panels are clearly trying to set up a character as the culprit while it is fairly obvious they can't be because of how cheesy it looks.

By the end of the manga, character descriptions for the main cast are explained, as many plot twists are told to the reader. Instead of it being discovered throughtout the story, everything is just said at the end. These plot twists are so ridiculous, the reader likely wrote them off as soon as they thought of them.

Predictably, the villain is a crazy person who is just messing with people because of a childhood trauma, through supernatural powers (which didn't exist until the very end).

In general, it is a very basic and uninvolved saw-like manga. For a better experience, simply the beggining of Danganronpa is able to achieve a much better version of this psychological horror guessing game.