A two-parter here
This is an extraordinary story. If you're who I think you are, your versatility and chameleon-like ability to change tones and slip inside the skins of wildly different characters and viewpoints is astonishing. Just extravagantly talented.
The sentence-by-sentence crafting of this fic is so brilliant. It's both lush and chiseled, finely detailed but with the slightly decadent perspective that comes of being filtered through Horace's POV. And what a beautiful character portrait - of both of them, really, but of Slughorn in particular, because it's strewn with so many subtle, perfect notes. All the canon qualities are there, only delicately realized instead of used in service to a caricature. I love that Horace approaches life as an Edwardian dandy would, a kind of down-at-heels Cecil Beaton but with a fuller silhouette and less celebrity cachet. The gentle, almost glancing way you show him appreciating the things about Benjamin Jink that are most Slytherin, and the things about Slughorn himself that mark him as a genteel, parasitic voluptuary with an excellent brain and an eccentric moral code - a Henry James sort of Slytherin - are just ravishing and perfectly voiced.
It was boorish for the host to empty a bottle, but it was a boorish sort of hour.
"Oh, I never." He paused. "Not since Albus took over, at least." Fantastic. That strikes directly to the core of what makes Slughorn so queasy a character, and yet makes the revelation almost charming because he's so childlike in his failure to recognize his own moral turpitude.
He drank to the most cunning, two-faced, duplicitous snake of a Slytherin he had ever had the pleasure of knowing.
There was something about an enfant terrible that never failed to drive him to foolishness.
Horace, still discombobulated, was nonetheless charmed. There was something very attractive about pertness - when Benjamin has just implicitly delivered a sneering rejection! Pert, eh? Takes one to know one. I marvel at how you have him size up Benjamin's rebuffs and retorts, and recast them as traits and feints to be savored. In a similar vein, I was fascinated by the number of times Slughorn pauses to reconsider exactly what he means and what he feels, doublechecking himself, attempting a version of honesty. He's a sifter and evaluator of shades of grey, and his own failures have left him yearning - not for the truth, perhaps, but for a way to live with the truth. To live with himself.
It was perhaps the most satisfying maybe he had ever received in a lifetime full of ambivalent responses. I adore this line. In hindsight, it says so much about Slughorn and the world's response to him, about his disappointments and how much this tiny, redemptive moment might mean, with its unspoken retrospective secrets and its sensual promise.
Also, just because it struck me as one of those profligate, inspired choices that looks so simple on the page but is impossible to pin down: I don't know why, but having Horace sing aloud, "...deep and crisp and e-ven..." was such an enchanting, fleeting shared moment between them, along with the hot cider stand, and Benjamin sipping delicately. It just made my heart swell.
In truth, Horace won me over with this line: a man who had died two years, seven months, and four days ago The preciseness of his memory drives home how powerful the loss was - how impossible to forget. Coupled with this acknowledgment: If it wasn't his business, it couldn't be his fault. How damning, and yet one has to give him credit because he knows it, he knows now, even if he didn't then, what his fastidious self-centeredness has wrought. It's partly why Severus's death haunts him. This is his canon cowardice, and his spiritual failure. A brilliant, unadorned insight that resonates throughout the fic.