As with most works of this genre, turn your brain off and enjoy. This one ticked me off too much though, so I failed in doing so and ended up leaving, seething with frustration at how nonsensical it is
The villains suffer from being excessively prepared. It's an absurd level of conspiracy. At this point there are clearly hundreds or possibly thousands of enemy special forces having infiltrated the kingdom with laboratory's and magic soldiers, and the kingdom is completely unaware except for a few individuals. That's bananas.
That said I've overall enjoyed it. I like watching our mc get all op and crush their plans. I just have to put some extra energy in to suspension off disbelief. Just wave my hands and never ask how the baddies got there.
8/10
Edit: the last several chapters have been a fight that doesn't seem to end. This author should avoid fight scenes or keep them short and impactful.
with any really good world building story it does take a bit to get it going good. This one isn't perfect, but the story does get better overall without to much overkill.
Then taking consideration of the main aspect of the storyline. The guy is actively attempting to Ret-Con a Game's Initial starting scenario. First players in the game arrive in a country at war! Save the X,Y,Z npcs etc etc.
So yeah, there's some kinda BS as author incorporates that into this and it is a bit rocky how it's implemented, but still interesting enough to keep it to read.