Art: Detailed backgrounds and a strong sense of spatiality allow for world building, while characters and action sequences are clean, crisp, and earnest.
Story: Unravels somewhat inconsistently, has a few exposition dump moments. But apart from them, the tension created from the spun web of alternating narratives drew me in.
Characters : what really drew me in, as all the characters feel memorable and fresh. Some characters are dumb, some are insecure, some are jealous, none are particularly cliché. Most importantly, the manga really highlights how duplicitous humans living in a post-apocalyptic world would really treat one another. Tons of tiny 'revelations' end up being dead ends or false starts instead of plot development because characters have been lied to or manipulated. It's great for character developments, as it allows (notably) our two voyagers to learn to navigate the world around them, but also avoids story beats from arriving too predictably in a satisfying way.
The side characters, as in both the staff of the orphanage and the settlement inhabitants / bandits / innkeepers the voyagers meet along the way are really stellar! They are also all visually interesting, and alongside the artist's detailed rendition of cool monsters and worn-down cities, really flesh out the world.
I guess I also need to address the 'gender swap' that occur not once but twice (!) in the first 27 chapters. Expected them to conveniently devolve into fanservice, but that hasn't featured too heavy-handedly yet. The fanservice is honestly super bearable (and I'd compare it to that of Chainsaw Man / Fire Punch fanservice, where one couuuld argue that it doubles as plot or char development). At the same time, the gender swaps don't seem to bring forth any trans identity narratives. The themes of gender will probably feature more prominently as the manga develops (voyagers about to enter a matriarchal village where men are treated like dogs), which will help us revisit these moments.
All in all, giving Tengoku a solid 7.5. While I wish the plot and characters were slightly more consistent, the worldbuilding and central mystery are intriguing and cool.
Art : 9
Story: 7
Characters: 6
Enjoyment: 8
Overall: 7.5
