This is a manga that was interesting for what was there between the lines so to speak rather than the actual things focused on in the plot. In terms of premise, it sets up an interesting premise in that a wife comes back to be with her husband in the past, which is a pretty unique relationship and the core of the manga. However, this is also all sorts of strange. Is the person in the past really the same as the one in the future, especially considering the major age gap between them? I would say that even though they kind of are, they really aren't. Hence, herbeing in love with him just based on the future is a very awkward relationship, which casts a shadow over the whole plot. This is resolved over time in a way, in that Rinosuke grows as a character, becoming someone who is capable of being loved and loving in return, and though he still has a personality that is childish in contrast to the future him, Marina still falls in love with him for real. However, this brings up all sorts of other issues. Primarily in that, since she's falling in love with someone who is different for the reason that they are different, that's kind of sort of cheating. Now while all of this isn't explored in such depth as I feel it could have been, it is acknowledged quite clearly, which ends up setting their whole relationship and plot on a very awkward trajectory, and one that doesn't seem to really have any sort of solid and satisfactory conclusion. In the end, the author decides that creating a solution that is satisfying and in line with the tone of the manga was the most important thing to do, and hence the plot bends over backwards in a way that doesn't really make much sense, but manages to reach a conclusion that is satisfying thematically. Hence, while I certainly can't say the plot is perfectly executed, I still think that overall it was quite solid in that it explored a unique relationship quite well, while the ending too was far from perfect it was still right in what the spirit of the ending should be even if there wasn't really any way to do a good implementation of such. There are side stories with various other characters, but they mostly fall flat outside of how they connect to the main relationship. I thought most all of them were jerks too, with the exception of the girl that confessed to him considering she was apologetic after being led around. The art I thought was really good, primarily in that Marina being incredibly cheerful came across very well.

tl;dr: A manga that sets up a very interesting relationship but has some trouble in how to bring it to its conclusion.