I feel as though Umibe no Onnanoko falls into the same pitfall of nearly every other story that tries to depict teenage romance/sexuality as something deeper than it actually is. Similarly to others, it lacks self-awareness required to properly tell these stories, and it aims straight to the 'punch in the gut' or 'shock value' to hold its narrative afloat. It's purposefully ambiguous, but, beneath that ambiguity lies absolutely nothing. It's a conservative layer atop that's trying to hide what lies beneath, but once you pull the curtain back, you realize that there's nothing there.
Greatest fault with Umibe no Onnanoko lies with the fact that it's trying to add more flavor/depth to the teenage angst than there is. In reality, teenage angst is just teenage angst. Sexually frustrated 14y old kids are everywhere, and part of fun in reading stories like these is remembering what it used to be like and comparing. Because, in the end, Umibe no Onnanoko is a journey of two sexually frustrated teenagers being assholes to one another, period. There's no flavor of depth anywhere to be found, and even bothering to mask its potential complexities is just a waste of time.
Narrative in UnO is broken. Structurally, it doesn't work. It attempts to be more than slice of life story but fails because there's no lingering trace throughout its chapters. Early chapters just feel as an excuse to see two characters have sex and nothing more. Everything about them is purposefully obscured, but it works against the narrative. Aim of the story, I suppose, was to see two characters grow through indulging in sex, but for it to work, we have to have a baseline for both of them. Point A from which they'll grow toward point B. That point A is just vaguely hinted at at the beginning, and by the time we get it, character development is already underway so it loses its purpose.
There's nothing wrong with adding layers to a character to make it more complex, but when details are integral to the starting point of the character, it's just destructive to hide it. From the start onward, there's very little 'plot'. If you remove First 7-8 chapters, nothing changes. There's a girl that got dumped and there's a guy with a 'pick from the bucket' trauma. Once you read the ending, it feels as though the entire point of the 'plot' was to reverse the situations of the characters. However, as far too much screen time is gifted to, quite honestly, pointless sex scenes (they were neither hot nor symbolic in any way, they were just sort of there), the journey to that reversal is so short I was simply never able to get a good grasp on it.
To sum that bucketload of info short, it fails to convey its point properly because it pointlessly hides information from the readers, and even when it gets to that 'point', it doesn't work because it's far too short for what it's trying to achieve.
Art is one thing I kind of liked in UnO. It's not mind-blowing to the point it blew my dick off, but it had certain charm. Yeah, the faces are weird, facial expressions are all over the place, but disregarding that, it had a life of its own. There are a few really nice shots (one that stood out for me was a reflection in street mirror, however basic it was), and it's not too busy with itself.
We finally get to the characters. They're, uh, sexually frustrated teens. It's kind of depressing how I can't point out a single other thing about their characters. I suppose they're an accurate description of 14y old teens, seeing as nobody knows who they actually are at that age, but this only cheapens the whole 'let's go for a deep story' segment that nearly all stories of this type go for. They're two similarly-faced drawings of opposite sexes that like to screw from time to time. Oh, and they're assholes to one another. And, of course, in the end, one of the characters goes through metamorphism of his, uh, 'personality' at the expense of the others' happiness or something.
It's hard to take these characters seriously, and therein the largest problem lies, something that I mentioned at the start of the review. The story takes the circumstances of these characters WAY too seriously to the point that it all loses impact. Its attempts at subtleties don't work because they aren't enhancers but rather integrals, and, in the end, you're left with a story that tried to be far too much.
In the end, though, it's probably one of the better (bad) teenage 'coming of age' stories. For all its faults, at least it's not 'too much in your face' with what it's trying to do. Yeah, ending is lackluster, 20th chapter is just pointless as it adds absolutely nothing besides saying 'oh, look, she moved on... kind of', but, in the end, for what it was, I enjoyed it somewhat. There are some cute moments between the two and even though sex part was really overplayed, I guess it's better than 'the girl is literally begging me to fuck her, but I'm too embarrassed to do it' stories.
Definitely not as good as some reviewers are claiming, but also not as bad. I've come across a lot of 'pointless sex' stories recently, and this has been one of the milder ones. Still, considering that first half is basically just two teenagers fucking, and second half is just your everyday teenage woe is me downward spiral, and ending is just nauseatingly trying to be more than it is, it's not a good manga by any stretch of the imagination.