Although sometimes the writing quality is a little workmanlike, this is a standout among original novels, with excellent pacing and excellent mech creation/mech fighting scenes, as well as a well-thought out galactic setting.
First off, it should be stated that this novel explicitly is a very genre novel, that focuses heavily on, well, mech design and combat, and as such your personal feelings towards the trappings of galactic sci-fi, hulking multi-ton humanoid robots, and incessant tinkering of mech design and loadouts is going to strongly influence your views of the story. Also, it's a System novel, that is to say, a mysterious AI cheat where he gains xp and levels up skills through a system, and it's also, less obviously, a cultivation novel where he progresses through tiers of mech design in a world where there his cheat bootstraps him out of the bottom of the bottom of the bottom into the concentric rings of power where even as he outpaces all his competition, there's always more competition of his age of equal or greater power to him, and there are 500-year-old masters out there.
Being a genre novel, it demands that the mech design and combats are done well, and in that, it can only be said that the author has succeeded. The thoughts of the MC are easy to follow in his design, and there's a good spread of his efforts and his results. While most of his designs are at least competent and clearly show his growth as a designer, some are merely competent, and others are great successes which show his future paths. The vagaries of the "real world" and various competitions do a good job of stretching him out of his competence zones and his plans for the future while remaining plausible. Overall, it's a reflection of the author's abilities, a reasonably intelligent MC with plans for the future whose plans and expenditures are often dictated by short-term need. At the same time, the authorities or other movels in the background behind such plot devices explain them reasonably so that they don't feel like contrivances, but actual tests or simply unpredictable events. Sometimes the MC makes bad decisions, but he often reflects on them at some point later, and sometimes he wins just by plain luck, but that's okay too - the nature of the world is clear - the MC has very little control of anything but his own actions and by and large, he's a small fish in a big pond.
The system, while inordinately powerful, doesn't overwhelm the story because of its fairly obtuse nature and the dependence on difficult-to-gain experience points (or design points, whatever). While the MC doesn't fully take advantage of the system (he would clearly progress faster if he focused solely on virtual gaming sales), it's understandable because he's truly in a sunk cost scenario, and besides, from a story perspective all the action is taking place in the real world. The story has a lot of long-term mysteries where the game isn't given away right away, and there's plentiful foreshadowing, whether it's the upcoming galactical upheaval of a new generation of mechs, the murky history of starship warfare, the system itself, potentially hostile alien empires on the fringes of human space, and of course, whereever in the heck the MC's father has disappeared to.
Minor characters are well-fleshed out, and all have their own motivations outside of the MC, which is contributed to by the strong world-building. Enemies don't obsess over the MC, and "bad guys" aren't unreasonably suicidal. Overall, it feels like a plausible, reasonable society. People for the most part do their jobs, have human desires, and although understandably many of the people the MC meets are ambitious or immature, everything is generally within the bounds of people who have grown up in societies that are largely controlled by rule of law, even the pirates and the young masters of the world. The MC himself is a classic loner, but not pathologically like so many MCs are. He has friends and rivals and no bizzare attitudes against working with others. He is a bit of an everyman, in that he doesn't really have any obvious strengths, nor any obvious weaknesses, or any particularly unusual moralities, but there's nothing really wrong with that.
There's quite a bit of leaning in the MC being a country bumpkin who is a frog-in-a-well, but compared to standard cultivation novels, I find this trope a lot more acceptable when you're working with galactic scales. "Cultivation advantages" of the rich and powerful that the MC has to face in a constant power curve is explained away with genetic modification. The nascent game world feels pretty weak and imbalanced to me, but as it's largely fallen by the wayside as the novel has progressed, this isn't a big deteriment to the story. More troubling is the bizarre economics/technology of the world, where the hinterlands are inexplicably generations behind the tech centers of the human race, especially as the novel takes the conceit that fabricators can cheaply pump out the most complex circuits and engines in a matter of minutes with virtually no labor involved - the novel goes into great detail multiple times how armor cladding is far and away the most expensive part of a mech because material cost dominates over production costs. Still, it's a fairly minor problem compared to many system/cultivation settings, just don't look too closely at the man behind the curtain.