After reading 43 chapters my conclusion is as follows: The manga is a middle of the road shonen action-adventure fantasy, however, it is rather competently handled, I would give it a solid 7.

The first chapter starts off interesting. I appreciated that when the manga tried to garner sympathy for the main hero, it didn't go for the usual overblown drama and tragedy. The first chapter had a somber, melancholic tone as the fatally wounded main character was stumbling through the ashes of the battlefield in a world that became a ruin, while he was reminiscing about his life and about the decisions that lead him there. However, the story is not really about that, the more sorrowful tone is quickly gone. Instead, the plot becomes a generic action-adventure story, because the MC decides to become a hero, to alter history, and he needs heroic acts to do so. However, the story is not really about that either, because it dwells into fantasy politics quickly, which seems to be the current direction of the story. While it's nothing new, the fantasy politics is competently handled and is an entertaining read.

The characters are a mixed bag, the story focuses more on the males of the main party, Kail and Seran. Kail, our MC, is fine, rather generic, but nothing particularly problematic. Seran is the one that seems to get the spotlight, he is the one we learn about the most, and he is the only really interesting character of the story. The problems start with the females, who are so bland, that despite the fact that I just finished reading the manga, I already can't remember their names. They were both love interest of the MC, but wherein they died one after another in the previous timeline, here they are both alive and well, so we get a love triangle right off the bat. Thankfully the story forgets about that for the most part, unfortunately, it also completely forgets about their characters, their combat abilities gets a little fleshed out, but not their personality. Even the side characters were more memorable than the women of the main party. Because of that, the only meaningful character interactions we get are the ones between Kail and Seran. The characters are overall not the strongest point of the manga.

All in all Tsuyokute New Saga is a rather generic fantasy story, which may not offer much, but what it does, handles fairly well. Some of the characters, however, really needs some fleshing out. I would give the manga a solid 7.