There will be not be many spoilers ahead; I haven't even finished the manga yet, but I really wanted to say something per se.

TL;DR
It's a great manga with confusing storyline but has developing characters and an astonishing art style, exploring maturity through a clueless boy's mind.

Throughout reading, my heart was pumping. This whole manga itself was quite unsettling and kept me on the edge, as an unknowing reader that was only trying to sympathize and translate its confusing content into our own experiences.

Punpun is an extremely interesting character. Its caricature is of a bird, seems to just be a blank canvas for the reader to draw its emotions and expression onto, though on some panels, he displays fear, uneasiness, etc. He idolizes and constantly reminds himself of sex and Aiko, which in turn divulges strange behavior on the main character's part.

Seeing the world from Punpun's eyes, you don't have a clue to what is going on, as the protagonist himself is walking on a disoriented path that seems to lead to a crude form of maturity.

All, I mean all characters have a psycho — no, not the right word, but has a ominous intention behind their actions. Let's see, there's a character that constantly lies for entertainment, and a character that just seems to make use of manipulation by threatening to kill you. There's basically an open playground for nutjobs to interact with one another.

One peculiar thing about the storyline; it seems to be all over the place. Though it portrays our lives itself, which is a chaos of different enactments happening at the same time, but in this manga, it seems to either be attacking you with an important storyline or beating around the bush just to show the character's development. I know that some elements of the manga need to be sacrificed for a greater cause, but it was a bit absurd reading some parts.

The art style; for the sake of putting it in, is just very off-putting, yet it draws attention, like it wants to ever so desperately want to convey the emotion the author is trying to put in.
And it worked, what can I say? It was an amazing experience.

Yeah, obviously, this manga isn't on the realistic side, unless you live in a neighborhood filled with semi-psychopaths communicating with one another.