What makes Knausgaard's narrative so powerful?

The first (of two?) parts of the first (of six) volumes of Karl Ove Knausgaard's My Struggle (A Death in the Family) ends with the self-named narrator learning that his parents are separating - in fact, divorced already - not a total shock to readers of course or even to KOK, as he'd seen increasing evidence of their living apart and one odd scene of his father in tears (and unaware he's being observed) - and in the last section KOK joins a party his father is hosting for his "colleagues" - fellow school teachers one would assume, his new girlfriend, and some cousins who had been long estranged from the family. In this scene, for the first time, KOK's father treats him kindly (is he just posturing for his friends, or is this a real transformation?) and like a mature adult (he's 16), offering him beer and not objecting when he smokes a cigarette. So we look back for a moment at where we've come: this half of the novel spans roughly 8 years of KOK's life, and we see him grow from a tearful and sensitive child into a pretty independent teen with friends and even a girlfriend, in other words, time moves on. There is one constant throughout this process of maturation: alcohol, specifically beer - KOK describes the incredible rush he felt on first getting drunk and from that time forward much of his time and effort is devoted to acquiring beer, for various parties in particular. His "maturation" involves his evolution from asking an older guy to buy for him to being able to buy on his own because he now looks old enough. What we also see is the dangerous onset of serious alcoholism: drinking himself to oblivion frequently. Alcohol becomes his social equalizer: he's blind drunk when he begins his relationship with his sober and straight girlfriend, Hanne - he has no recollection of their night together (chaste, but loving). In the last scene, he recalls getting drunk at a soccer camp in Denmark and dropping a lighted cigarette through someone's mail slot and into the foyer - and he's in agony wondering why he did this and if the house caught fire. Part of Knausgaard's genius is that he writes consistently with understatement: so many of these episodes and moments could be developed into big plot points - what if the house did burn down? what if KOK caused an accident or death through his drinking? what is the "death" in the family that looms over this volume? - but he keeps these elements in check; it's the very ordinary and familiar quality to KOK's life that makes this narrative so powerful: we don't feel as if we're reading fiction, as if this is a made-up life, but as if we are getting access directly to experience through a writer with an astonishing memory and a subtle yet detailed sense of time and place. Even the descriptions of some of the locales or homes - put forward with minimal but expertly chosen detail, simple language, unadorned, beautiful.