The most notable thing about Oshimi's approach to storytelling is his use of space. Very, very little actually happens in any given chapter. There may be a chapter titled "The Battle" (note: there isn't, this is just an example to avoid spoilers) and the chapter itself will only get to the point of the combatants meeting before anything breaks out. The actual battle starts in the next chapter, titled something like "Perdition" despite being the battle chapter. That sort of thing. A substantial amount of time is taken to express the breaths between thoughts and the jointed feeling of one's own speech when all that comes out are stutters. The start of a chapter could be someone getting provoked to slap someone else, and the rest of the chapter somehow takes place before the hand even connects with the face. That's why there's 153 chapters of this thing -- matters are stretched out in a way I imagine is intentional to convey the passage of time and counteract the quick speed readers are likely to scan over manga pages with. Even if you marathon this (which I recommend, given how action-packed the chapters aren't), you will find yourself frequently brought to halts to sit and think and dwell, just as Seiichi does. The pacing is at times excruciating, but in a way that I can't fault because it felt entirely with purpose to feed you into the character's mindset.
I feel like gaslighting as a concept is a difficult action to convey through any medium that can be re-read or re-watched, because you can always just review the reality of what occurred. Despite suffering from that exact problem (we, as the audience, witness and can go back to confirm what actually happened), Oshimi's depiction of the gradual and painful rewriting of traumatic memories feels credible.
Another point is that while this manga is not a beacon of unsubtlety, it does NOT take time to provide egregious explanations for why people feel certain ways or do certain things. Sometimes someone will look somewhere and you have to read their expression. This is somewhat of a low bar to clear in manga, but after reading Juujika no Rokunin, I'm desperate for a story that shows rather than tells lol. The distorted, warped reality that Seiichi attempts to navigate is grey, blurry, and inconstant. Is his mom evil? Are his actions justified? That's your job to figure out!
It's not a fun time and, tbh, I don't think it's a masterpiece either, but it's an emotionally compelling saga with noticeably calculated pacing that makes the pages fly by fast.