I haven't seen any very in-depth review of this manga, so I might as well try. Also, I feel this needs to be said because I don't see it anywhere, but trigger warning for rape mentions, an implied rape scene and implied incest in this manga. There's a few minor spoilers, but they're very very minor. There's an spoiler-free final veredict which sums up everything I said though.

Story: 4

The story is Dolls Code's absolutely weakest point. Let's go over it for a bit: the story is about a group of highschool students who have committed crimes and are now captured inside an evil school where they have to solve a variety of "Saw"-like challenges; the one who collects the most points during these challenges will be the only one allowed to leave and the rest will be left to die, basically. They also need to identify the fake "puppet" student to make sure he isn't the one win.
It has a very interesting premise that's enough to lure anyone into at the very least checking it out, and the writing does a very good job in immersing the reader into the story and keeping you curious, but the serious flaws cannot be ignored. Firstly, the premise itself has no justification at all in the world of this manga, the intent behind the main villain shaping the school in this "Saw" dynamic is never explained, and in fact, the more the story progresses the more you begin to realize it doesn't make sense for him to proceed this way to achieve his objective! At the same time, it is not explained why the villain had any knowledge about these kids and their crimes without having connections to the police, and the list goes of inconsistencies on. Secondly, although I completely get that this is just a two-shot, I must say the pacing feels incredibly rushed. The manga goes from plot-event to plot-event, without leaving any time for the reader to breathe. At first, this is enjoyable as it allows to read the manga faster, but after a while it gets a bit annoying. Due to this fast pacing and the already plot-centric rather than character-centric focus this story has, every friendship bond formed between the characters feel forced.

Characters: 5

The characters are, for the most part, likeable. They all have their own set of traits distinguish them from the rest of the cast, which is a very positive point. However, they remain at this: just a handful of certain traits, mashed together in a mediocre attempt of giving them personalities. Everyone in this manga is just an archetype. We have the typical good-guy anime protagonist, the mischievous twins, the smart hacker, the shy shota and the happy-go-lucky bishie who flirts with everyone giving some homoerotic subtext. The only character that I found unique was the no-organs dude with trust issues. Each character is given a backstory that explains why they did what they did, and these actually do work and make the viewer feel sympathetic for them. But character development doesn't exist in this manga, even if it wants to make you believe it does. Allow me to explain: during the course of this 10 chapter manga, the attitudes and behaviors of the characters do indeed change... but its sudden and mainly "off-camera" (meaning that they act a certain way in a chapter, and the next one they're suddenly a different person). Despite being static, none of the characters are annoying and they're enough to carry the plot. I WILL say that I find it incredibly disturbing to add a rapist character to the mix, and try to make the viewer sympathetic of him as well, like, geez... I get everyone is a criminal but in the end they had a, if not justifiable, at the very least understandable reason for their crime, (even the guy who committed a murder did it in self defense after being threatened), except for the rapist guy (which is good, as rape is so far the only crime I know which I find t be never justifiable). The fact that he is shown as "redeemed" in the end without ever explictly regretting what he did is pretty messed up.

Art: 6

I will admit that the art is good in this manga. The character designs are indeed generic, but given that the other aspects of this manga is pretty mediocre, they do stand out. Since that this was serialized with the shoujo demographic in mind, all the characters have a pretty face. And in fact, they don't suffer from same-face syndrome, something very common in anime aimed towards a female audience, which is a point to its favor. The art can also appropiately create a darker and creepier mood when it is required. The background design is nothing special, but since this manga occurs with the interior of an school as the only setting it is understandable.

Enjoyment: 6

Given that this manga has a very simple story that you don't really need to wrap your head around, and that the characters are indeed likeable like I mentioned, the negative aspects of this manga didn't really bother me as I was reading it, and I only noticed them when I thought about afterwards from a more analytical point of view. It is enjoyable as long as one has the mentality of this being just a "reading it to kill time" type of manga.

Final veredict (spoiler free):

For a two-shot, it really feels like this manga was severely biting more than it could chew. The premise itself might be interesting, but the character development is non-existent, the story lacks depth, and the pacing feels completely rushed. However, it features decent art and you will find the character backstories sentimental enough to walk out having developed a bond with at the very least one of them. I am confident that this manga would have worked way better if its focus was not in the plot, which is weak from the very beginning as it is never explained to the audience, but in the characters, who had way more potential to be fully fleshed. Although not 'good' per se, this is a pretty harmless read as long as you approach it without above average expectations.