Lots of bad grammar, lack of commas, questions without question marks etc.
The MC is introduced as a 185IQ genius. This was a major redflag early on, and it turned out to be an accurate one. He doesn't act like a genius. Not even near it. He is dragged around by the story, without planning or thought at all. This is a common thing of genius MC: you tell your readers he is but are incapable of showing how because you, yourself, are not.
At times, it seems the author thinks he is writing an action film, thus the pacing is terrible. One particularly bad case is when, just before a combat scene, one character "breaks into his home, climbs the stairs, wields the swords, looks at the closed door and kicks it down to find-" *changes POV*. WTF. This is NOT a movie! When the action starts, you let it roll! At each break in pacing, there's a chance your reader will get enough of your bullshit and drop the book.
The author is also inclined to introduce lengthy backstories about characters the reader has no reason to give a shit about, sometimes he doesn't even name them before flashing back to their past. Lots of backstories, lots of flashbacks.
Another VERY annoying thing is when the author writes the same thing twice, sometimes more, from different POVs. Man, choose one, the one you think is best for that particular scene or part of scene, and if you want to also introduce other characters, use them in later scenes. I don't want to read the same thing twice. I often skipped those.
The story is interesting enough to make it to 3 stars. The characters are not bad. A word of advice, though, the next book is not, unfortunately.