I absolutely love this manga. The theme of this manga is focused on regrets, fate, and hope. Everyone has regrets, sometimes the choices we make aren't the right choices, and it's all process of life. This is one of those 'what if we took the chance we couldn't back then' 'what if we were able to stop that event from happening' actually coming true. Yes, it is not possible that we could actually stop our past selves. But we should be honest with ourselves and prevent the regrets before it's too late. Fate does it's work, but don't be so set on it that it's just the way it's supposed to be and will be, because it isn't. I think that's what this manga is telling us. I also like how it points out
how much losing your loved one and suicide doesn't affect you only but everyone around you as well. Past Kakeru thought the gang would forget about him and are better off without him, but really, they aren't. I'm really glad the gang let him know that the future 'them' missed him terribly and still misses him.
I enjoyed the Parallel Worlds theme, not only because it won't affect the Naho of the present that married Suwa, but because it is a symbol of hope. The hope that you're doing okay in your own way in your own world and that the other you is doing okay too.
I really liked how Kakeru was complex and really mysterious at times, but very fragile and relatable.
One thing I could point out as a flaw, I felt like other than Kakeru and Naho, the gang felt a little forced, were like a typical shoujo background "friend" characters at times, and were not given as much depth as the Kakeru and Naho. Later in the series, I felt like Hagita was given more depth and I loved it. I just wished it was like that throughout and with the rest of them. One of my favorite part is that
Hagita actually broke Kakeru's bike ahead of time. It was so Hagita to do that, since he's the type that would really think hard and analyze the event itself to save Kakeru, not about why or how to prevent it in emotional sense but literally "stop" him from the event. It makes me realize every one of the gang is important and plays a role in stopping Kakeru, not just Naho and Suwa alone. Also nice that he was given depth and tense the plot a little with his analytical personality, but we get to also see the funny goofy side of him throughout.
The plot is not slow nor fast, it's perfectly paced. I do think there are things that could've been added near the end to make it feel more finished, but nothing is rushed to wrap up the story and it's great as it is. I like the nostalgic feeling this gives me, as if I was a part of this world. The plot just sucked me into the story.