What Pupa has crafted between these two characters in specific, it has managed to ignore in basically the rest of the side characters, characters whom often show up to drop a portion of information before leaving again, notable exceptions being Maria and Utsutsu's father. While Maria shows up more than other side characters, she is pretty much a vehicle of pure insanity that drives the story forward. It's easy to fault this as just lazy writing; it's also easy to say that fleshing out side characters is bad for the story, since the entire manga is Utsutsu and Yume's journey to stay together. What choice you choose to make from this is up to you.
Pupa's bleak story shows Utstsu trying not lose what is most important to him, but also the madness of him trying not to become what he hates the most. The longer Pupa goes on, the more it's shown that Utsutsu is a lot more like his father than he is willing to admit. The same shrewd look that his father would give becomes one of his own when he least expects it, and with it his father's more sadistic qualities of relishing in the pain of others. It becomes a part much later on where Utsutsu has to face the issue himself before being able to accept who he is and moving on.
The story itself suffers from a couple pacing issues, but does its best to try and show how Utsutsu and Yume deal with terrible situation after terrible situation. It's easy to say that until the final pages of the last chapter, nothing at all goes right for either of them. Pupa is basically a "Us vs. The World" story, but The World really, really, really hates Utsutsu and Yume. What Pupa gives in heartwarming reunions, it dishes out 3 times as much in absolutely insane situations to prove just how much Utsutsu and Yume need each other (more so how much Utsutsu needs Yume), to the point where if one was lost, the other can't live on.
A main driving force for the manga is the art itself. The level of detail added, especially to the final volume, is absolutely breathtaking. Besides the odd moments where Mogi Sayaka draws Pupa with a more cutesy look to it, the gore is drawn to a point where some of it made me sit there and just appreciate the effort that was put into the manga. The art itself does a good job of adding to the story, while not distracting yourself from it (it helps because the story gets outright ridiculous at times).
Is Pupa a manga that I'd read again? Probably. I will most likely just flip through pages of it again to appreciate the art itself. While the story itself might lose some of it's luster in that I know what the twists are as the story goes along, seeing how each character breaks is really bleak and entertaining stuff to read. Pupa isn't a read for everyone; it's going to make you accept some things in life that you would rather not dwell upon (child abuse, being left by your parents, dealing with shit you'd rather not), but it is still an enjoyable story to read nonetheless.
