THIS REVIEW CONTAINS MINOR SPOILERS

At the time of writing this review, I have finished reading the first 6 volumes

What I liked :

1) World building is decent, it's easy to grasp the geography - it's just one big continent surrounded by (very few) smaller ones as well as some islands, so you don't get a plethora of kingdoms. Most of the story occurs on the main continent and its kingdoms. There are fewer kingdoms compared to Earth's history, each kingdom has a few cities.

I guess the reason that the author didn't want to introduce more than a certain number of kingdoms was to allow him to keep things simpler for the reader - too many kingdoms equals too many characters and sub-plots.

I tend to appreciate this because you don't need an intensive revision of all the places/people that have been introduced in the previous volumes if you happen to take a break from reading this series. The lore presented in this new world is also interesting and devoid of any complexities, with many references to similar things from earth.

2) Lack of tsundere characters (so far). I despise most of such characters. Especially the loli tsundere trope.

3) Slight mystery element : Why was the MC really summoned, what's his real purpose? Who is this demon lord, does he even exist? Why did the demons show up? Why is this new world so similar to Earth, yet so different? MC also tries to figure out why or how magic works in this new world, since most others take it for granted - "It's magic. It just exists", and he tries to combine his knowledge from earth with magic in this new world to come up with creative ideas that aren't well explored but seem fun in the context of the series (giving it a SoL feel)

4) The side characters : Funny how their quality stands out more than the main characters despite getting lesser time. It probably shows that the author runs out of steam when given more time with characters than he knows what to do with.

What I disliked :

1) Main characters : There's not a single character that I genuinely liked.

Protag : Extremely unrealistically written and consistently exhibits cringe-worthy behavior, yet is considered very normal in the context of the series. For e.g., he's just a university student under 20 years of age, but even when he is summoned in this whole new world for the first time, he doesn't panic. He's able to keep a calm mind and even takes over the throne right away when he is asked to, and gets to work. There was a bit of tension (positive) at the start of the series when he becomes the king, due to opposition from top military leaders, but even that is proven to be just a ploy to weed out some corrupt nobles. He comes up with flawless plans which are successfully implemented, the public falls in love with him, all the talented personnel he hires are loyal despite MC being so young. He's shown to have wisdom unnatural of someone his age (despite being from a modern world he adapts to his new role as a king in this world flawlessly, outwitting the best of minds/rulers in this world). Despite this he's unable to think of something simple like birth control (condoms have existed in one form or the other on earth for centuries) so he avoids sleeping with anyone since he doesn't want to have a kid until things are more stable (but finally gives in when he decides it's safe to have a kid - and now she's pregnant. There are several volumes to go but one of his wives is already pregnant. MC is just 20 years old by this point). Everything he does or says when it comes to his harem is cheesy. Like not realizing why a girl fell for him despite changing her life and accepting her when no one else would, and saying things like "I just did this and that. I wonder what made her fall for me" or "I'm sure I will fall in love with her" - Concept of love in this series is just another joke.

He's never been with a girl before, yet acts nonchalantly around his harem, but then tends to feel pretty embarrassed when he's flirting. But just to mess up the character even more, the author makes him do things like patting girls heads to comfort them, suddenly hugging them, or even humming some "anime song from my world" (fml) when he's around them without any hint of awkwardness. Plus almost no one hates him, and those who do eventually come to like him and at times even devote themselves to him.

I used to think that the Isekai Smartphone MC was boring, but no, this guy takes the cake.

The harem : When each one is introduced things seem like they might get exciting, but not a single one of them so far has made me feel even a hint of interest in them after their initial appearance. Once they fall for MC, they are just pushed aside to make way for new members. This is also typical of many harem LNs, but I feel something like Arifureta handles the harem element much better since there's actual progress for each character.

They have bland, cliche personalities (a dignified princess, a gluttonous warrior princess, one with the mature aura, one with the imouto aura, a shut-in, and so on), and even though they have some unique skills of their own, they just come across as "his harem" and nothing more. As another review has stated, there's hardly any jealousy, and there's no conflict between them - they just get along extremely well as if being pre-programmed to be the best support possible for the MC.

2) The art : Poor. Even the characters' faces are boring. Every other LN I have read has had much better art than this one. The art depicts the characters like some kind of mannequins (just look at the abominations they call hands and fingers), and there's hardly any background shown (as if they are standing in someone's dream). But this aspect isn't that important to me, so it doesn't weigh in much for the overall score.

3) The tangents : There's only one other review that points this out, and it's the biggest issue I have with this series - MC (and at times the others) go off on a tangent to explain things, thus taking the steam out of the current situation every single time. These explanations go on for several pages, are usually pointless and add almost nothing of value to the plot or understanding of the plot. They are extremely tedious to get through too; after the first 2 volumes I started skimming through them to get back to the conversation between the characters.

One example from vol.6 : By this point it had been established thoroughly that the MC had an ability that allowed him to interpret this new world's language(s) just as naturally as he could interpret Japanese. In vol.6, he hears a mysterious voice that he is able to understand but his companion is not. Yet it takes someone else to point out the possibility to him that it's his ability that might have allowed him to understand the meaning behind the words. Only then our "greatest king" seems to realize it, and then the author goes off on a tangent for 2-3 paragraphs explaining that ability all over again. With examples. Only after that he gets back to the conversation (Also, this felt like the author intentionally dumbed down the ever-so-smart MC just so that the side character would have a chance to say something meaningful.)

And this brings us to the wasted potential of this LN. As the title would have you expect, things are about rebuilding the kingdom in the beginning, thanks to MC's unique knowledge from earth (social reforms, variety of foods, etc.)

He takes some excerpts from Machiavelli's writings and also "The art of war" to explain certain things to the other characters in the series as well as the readers, which in the beginning fits well with the rebuilding aspects, but after the first few references, it just comes across as pompous.

And after this initial development, it's a lot about irrelevant sub-plots. Broadcasting idol shows? Broadcasting kids education shows? I don't want to read through tons of pages just to know how he set this up and which people he hired, why he hired them, etc. Are there no other problems in the kingdom? They became a superpower in a year? What about conflicts with other kingdoms? Kingdoms eyeing their rapid progress? Where's the tension from the invasion by demons? How about looking for some dungeons (since they seem to have a lot of mysteries about ancient technology that helps his kingdom)?

Everything of any significance is handled so easily that I don't even know anymore what this LN is trying to do. It is becoming increasingly boring and frustrating to read it compared to the first volume. At present it just comes across as the author writing about his ideal version of a non-combat isekai hero, someone who's cool, calm and collected in most situations, yet easily surprised/flustered when it comes to the antics of the girls in his harem. Wiser but also younger than most other characters (rulers or people in high positions, some having lived for hundreds of years). Someone who wants to "protect his family". A character that always amazes the rest of them with his wisdom and quick-thinking, and then shows humility when showered with their praise. Everyone supports him. Destined to be the savior from the beginning.

This feels more like a kids novel. The author even gives away information about the future (e.g. "years later there would be stories about so and so incident"), so you have a guarantee that everything is going to turn out alright.

I still enjoy bits and pieces of the volumes, but the enjoyment factor is rapidly going down. The amount I'm skimming through makes it feel like work instead. The only reason I am continuing to read it (though I might just drop this LN and move on) is because of the aforementioned mystery elements after already having put so much time into reading it.

Overall : 5/10