I'm at chapter 14 or so right now but I did read the
TVTropes page for this, which pretty much spoils the entirety of the rest of the plot at least according to the Webnovel version.
Based on what I've read so far and the probable direction that the series is going in unless it diverges from the WN, I feel like this is a lot of squandered potential.
The basic plot: Adult guy is isekai'd into the world of an otome game (that his sister made him play, you guys. He totally didn't play it himself because apparently that'd be gay or something), but instead of being reborn into a character with plot relevance he is instead some random nobody commoner villager mob from the castle town he and his mother live in. So right away he has no power or influence or story importance from which to effect the rest of the world or the plot. But he knows that if the game plot continues to unfold unchecked, it will result in the villainess character falling to ruin, descending into darkness and madness, and kicking off a massive war that will kill a ton of people and wipe out the town our MC lives in, killing him, his mom, and pretty much everyone else he knows and cares about. Plus the MC admits that from his time playing the game, the villainess girl was the only character he found remotely interesting as the things that led to her being ostracized and crushed were not typical game villain traits like her being a haughty bitch who abuses everyone. Instead as he's seen now that he's in the world, her behavior is more about her concern for the safety of the kingdom and the ways in which her prince fiance and other characters around her have their otome-game behavior potentially causing issues that could harm the populous. So he sets out to stop the tragic end of the villainess in order to save her and prevent his home from being destroyed. And in order to do that he uses his knowledge of the game to sequence break, cheat, and grind up so that he can have the power and potential to truly impact the story, all with him having started without an isekai-standard god-granted cheat ability.
And if you don't care about being spoiled, here's what I can glean from the TVTropes page about where the rest of the story goes:
The game's protagonist girl ends up also being a reincarnator. But because she is in the role of the main character and she knows everything about the game since she's a super-fan, she of course becomes a shallow, selfish bitch who expects to get everything she wants and to score the reverse harem ending even though that leads to the aforementioend war. She shows zero concern for anyone else and even though the Villainess girl is not truly that bad, the FMC reincarnator still thinks that she needs to fall, be broken, be raped, and die in ruin because she's the game's villain and that's what's supposed to happen. So the whole plot is her recklessly trying to push the plot ahead as it's "supposed" to go while Allan fights against it.
Meanwhile He and the villainess girl finally meet up and work together, eventually falling in love. By the end Allan defeats the game MC girl, prevents the massive war from killing everyone, saves the villainess and prevents her fall and is able to become a noble who can marry the villainess without repercussion. The game MC basically then ends up suffering the villainess' fate in her stead as karmic punishment for her spoiled selfishness.
But here's the thing, from there this takes almost every wrong turn that it can.
-15 chapters in and the villainess who is, essentially, the female lead has not appeared outside of a cameo in the earliest stages of the story. So the major reason that the plot is happening is not present.
-While it's great that Allan has a plan to make himself strong and useful, he also spends a lot of time doing other stuff that is not really treated as being as valuable. Or he talks about the importance of some things but then ignores them. Like how he needs to train his swordsmanship up for later but we never see him actually using a sword because....
-The author uses some alchemy/creation magic nonsense to allow Allen to just make all sorts of fancy tech. Specifically and especially guns. He starts by making a plane/glider powered by magic which sort of halfway makes sense because in his past life he had an aeronautical engineering degree, but then he also makes perfectly working guns of just about every style imaginable. Even after his narration explicitly says that making complex machinery requires precise understanding of how it works.
-the guns make most of the fights boring as he's rarely in any real danger because of them and any time it feels like his power is slipping he just introduces another powerful gun that swings things back in his favor.
-The author also very clearly has a Russian gun fetish. That's not necessarily a con, but it is kind of odd. I'd expect most enthusiasts of any sort of technology to have their favorite types and models, but his almost exclusive love of Russian stuff feels oddly specific and a little weird. But in spite of his very detailed gun fetishism, he also makes some mistakes with understanding how guns and their ammo work. Most notably as someone mentions in one chapter's comment thread he starts talking about bullet types and ends up calling one design something suitable for hunting even though it's basically the exact opposite.
-It's good that there are some decent, reasonable adult opinions and reactions from him. He doesn't turn into a screaming ninny at the prospect of sex (rather he tends to be annoyed or put off by sexual advances because he's so hyper-focused on getting to the villainess girl) and he has a fairly nuanced view of killing (he struggles at first with killing animals but gets over it. But even after that he recognizes that there's weight to taking a human life and can't bring himself to do that easily. It gets him chewed out by a character who has a much more simple worldview and he sorta gets past it, but he still manages to not come across as an unflinching psycho who will cut people down even if he thinks they "deserve" it for being bad. The problem with this is that this level of introspection feels a little uneven with the rest of the plot.
-From what I've read of the spoilers for the rest of the story this ends up discarding a lot of what made it different and unique and just ends up playing out like other more popular stories about characters reincarnated into otome games or trying to prevent villainess downfalls. The characters are never as interesting or well-rounded as other, better series. The villains are all petty, simple, shallow, unrepentant bastards who routinely take the stupidest possible path just because it's the most petty and evil. The good characters are strong, noble, right-minded, and well-behaved even in the face of hardship.
-The art is... fine. It's not terrible, but it's not that great.
I don't know if I'm gonna stick with this for much longer. Maybe I'll just leave it on the "on hold" list to see if eventually I can speedrun the chapters until I get sick of it. But right now I only feel like it promised me something original and interesting but delivered something that's the same as everything else, but worse.