Gotta admit, I REALLY like this one. Instead of being obsessed with power, or violence, or sex, or any one of the hundreds of standard fantasy fantasies that most isekai manga tend to gravitate towards, this is about a man whose only interest is in pursuing his hobbies. It's...gentle, in a way that I don't often see.
It really feels like more of a character study than a fantasy story, though admittedly there isn't a lot of material to set that view in stone. Eizo really just feels like someone who likes to focus on his passions, and the fact that he doesn't expect anything from people around him aside from what they're willing to give freely is a pleasant change of pace from the common standard.
I think there is definitely room for improvement in this area - I would have liked the difficulties in a man with contemporary social mores regarding construction of devices meant to kill be a constant throughline, rather than the "hey, don't worry about it" "Oh okay, that makes sense" resolution we got, but it could easily get a revisit.
Not gonna lie, the casting vs. Smithing argument has no small validity here, and anyone who's spent even an hour watching YouTube would know not to make that mistake. Maybe that was intentional for a future plotline to show how broken his skill really is, maybe it was done through authorial ignorance. Like with a lot of niggling issues, there's not enough source material to judge.
I'm actually enjoying the lack of overt romance - Eizo is taking time to focus on himself in a way he clearly never had the opportunity before, and it's been said that women are interested in men who have a strong passion other than them. The fact that he's clearly an interest to at least two of the four women introduced so far is fun, especially since none of them are either acting in the standard pick me mentality nor engaging in the toxic "you'll like me because I low key abuse/take advantage of you" bullshit popularized by the likes of Love Hina and Ranma 1/2.
It's sweet. It's slow. It has some pretty good art, throwback 80s in style but with the precision and refinement of the late 90s/early 00s that saw manga and anime really explode. Take a look at the female centric panels - fellow really does know how to draw attractive, emotive women without throwing tits and ass everywhere. Even what little nudity we do see is situational and hardly sexual. 8.5/10 and I'd probably score it higher if there was more material.