he used gatling guns to wipe out all of the newbie dungeon lord's army in the noob battle, or when he bypasses every single trap his opponent sets up.

Procell's the MC and he's a Demon Lord with the ability of [Creation]. Every Demon Lord has one such ability, like [Beast], [Wind], [Alchemy] and so on; each ability grants some powers to the Demon Lord and the ability to create minions of varied capabilities. Procell's [Creation] power allows him to create any object from his memory out of thin air. And for some reason, he has modern-day knowledge (in a european medieval fantasy-type world), so he immediately creates some modern weapons like pistols, rifles etc.

It baffles me that the MC limits his own OP ability to the creation of some 4 or 5 weapons when he could totally overhaul the world he lives in and how its warfare is made with some small stuff like radios for instant communication between troops, night vision goggles, watches, cameras or, idk, some better clothing or armor. In one instance he does create a pair of binoculars, but it's never mentioned again and no one acts with any curiosity towards it. Also, although he does create some computers for Elder Dwarf (one of the main characters and a general in Procell's army) to work with, he does not create other similar devices, like smartphones or any other electronic device whatsoever (and even the computers he made, they're of exclusive use of the Elder Dwarf), which's pretty dumb. ED's computers are powered by a diesel engine, but it never occurs to MC or ED to expand the usefulness of electricity or combustion-powered machines.

What I'm trying to say is that the author dropped the ball hard on the creative department when it comes to MC's powers' versatility. There is some kind of explanation for that, but it's not very convincing and also doesn't tackle this issue directly.

Up until now there's barely any character growth, but that's OK I guess, since we're still in the beginning of the story. That said, if you like the characters as they are now, you'll most likely like them for the months to come, but I find them rather bland and one-dimensional stereotypes. The MC doesn't truly have a personality, he's just "a nice guy" and the rest of his troup's mainly composed by japanese tropes. As for antagonists, it's quite depressing that the first true villain of the series was the moustache-twirling-kind of villain and he's dealt with pretty easily and effortlessly, not only because he's weak, but because of some bullsh*t cheating by MC's crew during their fight. It's all smooth sailing for our heroes, who never seem to be in any kind of danger or pinch whatsoever - if you're faint of heart and rather take it easy or if you don't like plot twists or major turn of events, then this story's for you.

As for the city-building part of the story, I must say it's pretty lazy and undetailed. We never see anything happening, but get reports from time to time of how things are developing. MC's city's infrastructure's mainly built offscreen by Elder Dwarf and her helpers and the author does not think it's interesting to delve into city planning or things like that. Things just work, don't ask me why. There's no modern structures in this city and MC doesn't give any input or insight towards this area, he just lets things flow naturally. There no drama here.

All in all, this novel's more slice of life than anything else. Very lukewarm, tame and easy-going. Everyone's nice to everybody else, there's always giggles and cute stuff happening everywhere and everything our heroes set out to do turns out successfully, there's no setback at all in anything, it's all handled perfectly. Is there cruelty and evil happening in this world? Sure. But not to our main cast and their marvelous city.

So... Yeah. 3 stars.

how can he build a city out of nowhere, without anyone's permission? It will be realistic if it's away from civilization but he is just walking distance away from another city with a capacity of 100, 000 people. So logically speaking the land is within protection of that said city and I doubt the governor of that gigantic city will allow another city built in between a dungeon and his city because he will lose resources. He is suppose to be smart..?

He build a freaking city out of nowhere without asking any land lords. I mean it's a freaking medieval period, a royalty or a nobel should have ownership to the land especially one near a freaking city. And assumes that he will be the governor just because he build it? I don't think life is that easy, especially on medieval period and force can't be used once a nobel or a royalty makes a move since it will be an all out war from there.

He only asked permission from another demon lord. The setting is way to unrealistic.

Such as Unique Monster Creations, Gathering skills/creature types from other dungeons, creating a city for humans to live in, even fight for my protection (their own home), Small other world introductions, such as city management, apple pie, a casino.

He can create firearms of any kind essentially at will over long term. Short term is limited by his mana, which is still pretty allowable. They are as powerful as you'd expect against fantasy people.

He can also create legendary monsters with certain relatively lax conditions at will. Other dungeon masters have 33% chance of getting A rank with the same method (B otherwise), MC pulls S rank at 100%. Yeah.

Now combined these two points make him broken OP. At one point 3 other dungeon masters ganged up on MC under favourable rules to them and had powerful monsters supplied by older dungeon masters. They got defeated with barely any difficulty.

When they get to city building phase it's used to pull workforce out of nowhere. Need more smiths? Here's some master smiths out of thin air. No effort required.

There's the fox girl, dwarf smith that is good at building stuff and flying elf. They all love their "father" and want to be of use to him. Oh, and the male undead butler dragon and the yet unnamed water girl. They also love their "father" and want to be of use to him.

MC was getting corrupted by him being a demon lord if he used a power. How was this solved? Have a subordinate call a powerful subordinate to whack the MC every time he seemed to go out of control until he realized that going out of control was silly. Normal subordinates cannot harm demon lords, but conveniently he had just acquired a subordinate powerful enough to have a subordinate of their own of that level.

MC is giving off great deals one after another and no one is suspicious of things being too good to be true. Say, the casino. MC decided that his city needed a casino, so he went for a business partner. 90% payback rate wasn't good enough, so MC built the facility and compensated with the city's income for the partner to handle the casino. Yeah, definitely not a suspiciously good deal. Or the time MC just claimed to be a god to counter another hostile religion encroaching his city and everyone in his city simply accepted it.