I absolutley loved this anime...and its ability to make me cry every couple episodes with just the feelings and emotions within it. I'd also recommend this anime to pretty much everyone.
That's not to say it doesn't have shortcomings, and I'll unfortunately have to go into spoiler territory to touch upon the parts I felt were contrived and even a little annoying, but the rest of the review will be spoiler-free.
The spoiler parts will be under the "Overall" title at the end, so just stop reading there if you don't want spoilers.
Now that said, I'm not going to gloss over that this anime deals with suicide...and actually deals with it quite well, including the state of mind of a suicidal character.
In fact, one of the reasons I rated it so highly (despite some issues it has) is because it did manage to still cover such a deep topic and capture the state of mind.
A group of five people meet to dig up a time capsule from when they were 17 years old. It's been ten years since they buried the capsule, and along with it came strong feelings for their sixth member who is missing from the group.
At the same time, the 16-17 year old of one of the protagonists, Naho, finds a letter addressed to her...from herself. Upon opening it and reading it between events on the first day of school, she finds that everything the letter predicts actually happens.
While she's still in doubt at first (and also doesn't realize the impact of an event she was supposed to stop), she quickly realizes that the events in the letter are true and that it's really from the future (or a parallel timeline).
When Naho realizes it, she (and her friends) have to do everything they can to prevent their new friend's death.
During this, Naho and Kakeru start to fall in love with each other. One issue I have (which doesn't involve spoilers) is that some of their relationship feels a little "forced" in how just painfully awkward the two are. While some romance animes have that sort of "painful awkwardness", this one felt a little too far reaching on that at various times.
There were some scenes where I prayed it wouldn't spend too long on just how awkward those two can get between each other since they're so similar in not being good at expressing their feelings. Sometimes, the story felt a little drawn out or only managing to be perpetuated thanks to Suwa's character.
The characters are interesting, though the female protagonist can sometimes get a bit annoying in how much she relies on the letter down to following the same path taken in the letter (despite it telling her exactly what was done to try and change it). All of them are important and a tight-knit group of friends (portrayed rather realistically as well), but I'm just going to list the main three.
Naho Takamiya is the female protagonist, and is a very reserved and shy/formal girl who typically tries to shoulder everything to try not to burden others. It is quickly revealed that in the future timeline, she is happily married to Suwa (and even has a child), but seems to have feelings for Kakeru as well...and not just ones to prevent his death. When she gets the letter, she quickly accepts it as the truth...but often messes up by using it too much as a guideline.
Kakeru Naruse is a difficult character to pin down. Like Naho, he also tends to shoulder burdens on himself without telling others about them to the point of forcing a smile even when he's hurting. He has a complicated situation with his mother and family, and always seems to be teetering on the edge of something darker even though he is afraid of hurting others. That fear often holds him back from admitting his feelings for Naho, so he often needs to be prompted.
Hiroto Suwa is the "all around nice guy" character, but isn't annoying about it. Rather, he puts other people before himself and come to terms with any possible regrets about those actions. He's often the "wingman" in the relationship between Naho and Kakeru, and not many people can honestly do what he managed to do in the series in regards to his own personal feelings.
To be honest, the major portion of the character score is thanks to Suwa. Without him (and glasses-guy) in the anime, it would have been just another dull and cringy romance.
Sound & Animation
I honestly wasn't fond of the opening song, but I did like the ending song. The BGM felt like it was in the proper places, but isn't memorable or anything except the times it sounded too loud. The voice acting (Japanese) was done extremely well and definitely helped to bring out the feelings of sorrow or "moved to tears" or joy which the characters experience.
The animation could go from "fine" to "meh", and distinguished the characters so there was no question as to who was who. Even scenes where they stood around talking felt "lively". The animation focuses a lot on the facial expressions (particularly the eyes) of Naho and Kakeru to express their thoughts, but still manages to make the emotions in the scene and characters obvious enough via that so that even someone who has trouble reading body language (like me) was able to understand it.
There are a couple moments where the situation feels like "plot convenience" (especially towards the end).
Once again, I'm going to give a warning of SPOILERS as I point these out. I just can't really talk too much about the major cons of the anime without going into spoiler territory, sadly. Besides the feeling of some of the developing romantic relationship feeling awkward to nearly the point of cringy, the thing I have a major issue with is in the final couple episodes.
So again, SPOILERS BELOW.
Don't say I didn't warn you!
My major complaint comes at when the letters say that Naho and Kakeru will have a fight on New Year's Eve; this fight is part of what leads to his suicide.
In the letter to Naho, besides it telling her to "speak carefully and try not to hurt him", it also details exactly what the Naho of that timeline had said which hurt him.
So, what does our Naho do?
Proceeds to say exactly the same thing.
The scene had me facepalming and actually grumbling out loud at the screen, because it was just so completely idiotic.
At this point, there was no doubt that the letters were legit; there should have been no reason to doubt them.
While I can excuse the others inviting Kakeru to hang out with them as that they just hadn't read theirs yet (though this is only actually stated for sure in Suwa's case), there is no reason for them to doubt anything the letters tell them so long as it's still lining up with the current events.
As soon as Kakeru started to talk about his grandmother, Naho knew it was going to come up and should have been prepared to at least not say the same exact thing that alternate-timeline-Naho said.
When Kakeru (rightfully) got angry, it was supposed to be an emotional scene since it was their "first fight" and all...but all I could do was rage at the screen. It was actually the first "sad" scene I didn't cry at because I was just so pissed off at how Naho followed the letter instead of tried to say something else.
I mean, wouldn't anyone (even if they didn't know what would happen in the future), say "Go ahead, be with your grandmother?" to Kakeru in that situation? It's fine to say "you're not alone", but then follow it up with "but I understand you're worried, so go ahead and be with your grandmother"...or something.
And I'm a freaking social disaster! If a social disaster knows to say that much (even when I was that age), then I cannot forgive Naho's absolute stupidity.
It was as if she decided to just let the events happen the exact same way because she was afraid that deviating from them would put her in uncharted territory.
If they didn't argue in that spot, and then later had some sort of argument due to Naho saying something insensitive accidentally, that would have been hundreds of times better than the situation just freaking repeating! It would also show a little more just how this timeline is diverging.
And even though Kakeru got a head start when he stormed off, he was walking. He also even paused on the sidewalk after a little while. How was Naho unable to catch up with him when she was running? Am I to understand that she just gave up when she was in that parking lot?
I get that this isn't like Steins;Gate in that it doesn't exactly focus on the parallel universes/diverging timelines and the butterfly effect, and only tells the viewer just enough for them to understand about that aspect of quantum theory...but at one point they had stopped using the letters as a "guide" and just went with their own feelings...
...or tried to, as Naho wound up turning to it again. Turning to it again is fine, but following the events written down on it, down to what was said? No. That's not okay. Not from the plot standpoint, and not from a writing standpoint. Instead, it just felt like it was convenient that Naho chose to do exactly what her alternate-self did during that moment.
It felt like the writer decided that they wanted to have the "climax" of the anime soon, and to just use that event because "well, I already had it happen once before in the first timeline" instead of coming up with a different situation where the two can get into an argument (because the feelings of Kakeru cutting off ties due to his extreme fear of hurting her, while stupid in its own right, needed to come out before their relationship could move forward).
Same with the Valentine's Chocolate situation. Instead of giving the chocolates to him early or taking initiative by branching off of what the letter said as instances (when she just let him walk past in the hallway, I nearly screamed)...she waited until it was already following the pattern of what happened in the original timeline.
And even then, she barely made it (and might not have if her friends hadn't put that note in his locker; pretty sure that's where it came from...most likely Suwa since he was so confident that she would make it in time). Wasn't that convenient to stir up drama and suspense.
So, I can't give this anime full points because at least episodes 11 through mid-13 just...no. I couldn't even get into any of the painful feelings the characters were having then because I kept thinking "well if you hadn't gone and done exactly the same thing the letter told you not to do..."...
And no matter how much I like this anime, I can't let that go in a review. Even so, this anime is certainly "above average" though I can't see watching it more than once (as it hit me in the feels so many times that I nearly ran out of tears by the end).