This is a comedy manga about a boy who goes back in time to restore the spirits of his mother. At the start of the manga, the story relies on humor and doesn't take itself seriously at all. I think this is the best bit. Towards the middle the plot takes a backseat to little standalone stories that don't really add anything to the narrative. The story remains somewhat entertaining in these chapters but the humor definitely degrades. As the final chapters approach the story takes on a more dramatic tone as the author begins to wrap things up. I think the main plotline about the protagonist saving his mother is wrapped up well enough for a gag manga. That isn't to say that it is well written or at all memorable but it resolves things and makes sense. However, this story also has a romance subplot. Or rather, the author suddenly decides to take the romance b-plot seriously in the last couple chapters. The problem is, up until that point that protagonist has paid no attention to that b-plot for the entirety of the storyline. So in order to resolve things the protagonist's thoughts have to magically change with no explanation because if he keeps being himself then the romance can't resolve in a dramatic way.
tl;dr This is a gag manga about time travel with funny moments but a subpar plot that ends with a dramatic but unsatisfying conclusion that doesn't fit the tone of the rest of the story .