So... My first impression of Koe no Katachi was overall my generic reaction to the synopsis of a Slice of Life. It could go anywhere, be anything, turn out great or be something I wish I'd never read. Needless to say, what I got was not what I expected.
This manga, which I can best summarize as something along the lines of Bakuman meets AnoHana, greeted me with a punch right to the face. From the very beginning, I knew exactly what kind of manga this was going to be. Even still, I was beyond surprised by what I got.
Story: 9
While I feel the story deserves a 10, I must acknowledge that it is more or less what can be expected when one thinks of Slice of Life. That still doesn't do anything to decrease the utter risks this manga takes with its story. It goes to great bounds to reflect the countless issues that surface from bullying and the lasting effects it can have on people. Not only that, but a huge undeying message is that no matter how a person acts, there is always something beneath that facade that people would be shocked to find. Including many sensitive topics such as suicide and how fake most friendships are, this manga takes it all and throws together a beautiful tale of a young man trying to right the countless wrongs he committed in the past while trying to find what it truly means to have a "friend".
Character: 9
There isn't all that much that can be said character-wise without spoiling a great amount of the story. However, what I can say, is that each of the main cast and even some of the far lesser characters get incredible development. Obviously, there will be instances of you wanting one or two of the characters to just drop dead, because they're horrible people. But that's the brilliant thing about Koe no Katachi. Each character knows exactly who they are, and... It tied directly into who they are. I really can't say more without aforementioned spoilers, but...
Art: 9
The artwork in Koe no Katachi is very unique. It is unlike any I've seen before, and it is wholly fitting to the tone that Koe no Katachi went for. Maintaining an air of realism, which was a huge part of what made this manga, the art does exactly what it needs to and plays a huge part in evoking the emotional response that a scene calls for. While it is unique, however, it is also more or less kind of what one expects to see in a Slice of Life. I know I'm really driving that point home, but it's true.
Enjoyment: 10
While Koe no Katachi was by no means perfect, I could not stop reading. Literally. When I wasn't messaging friends or taking care of something, I was reading it. It was to the point that I finished it within seven hours. It does exceptionally well in drawing the reader in with compelling characters and brilliant writing that all go together in creating a work of art that makes you care for everything that happens to each character.
Overall: 10
As amazing as I think the manga is, I must continue to drive home the point that it is still a Slice of Life, and it goes to no great effort to hide that fact. While that isn't a bad thing, it also holds it back a bit from being something even better than what it already is.