The best parts of the story (the apology and the reunion) were things you'd already previewed, and they set a high bar that the rest of the story didn't really clear. Finding out the reason for Reimu's visit was interesting, though the repetition (finding out first at Saint-Ulrich) hurt the pacing a little. Reimu would definitely be "shoot first, ask questions later" about this, as she tends to be in canon, and her prejudice against youkai fits as well.

I think the worst part for me was that (a) she lost to Gryphon, (b) we don't get to see it happen, and (c) she needed to have lost to change her mind. I really like your fight scenes. You tie together choreography and character building in ways evem few published authors do. So I got super hype for the fight that was doubtless about to happen and then nothing.

I'm not directly opposed to the idea that Gryphon could beat Reimu, but I feel it requires proof, it requires showing your work. Canonically, she has beaten immortals, she has beaten swordmasters, she has beaten wielders of strange magic. So his victory feels like a "dude, just trust me".

The stuff that happens because of the fight is a given. Gryph isn't going to go, "Yes, I'm a dangerous abomination like Nero and Rasputin" no matter who wins, and aside from everything else, I don't think Reimu has the authority to kill him without risking a war between Fuso and Karlsland (and also it'd cause a time paradox, since there's lots of things in the main universe G needs to be alive for).

I feel like it'd be more interesting for Reimu to change her mind despite winning her battle with him. For instance, she might not find any evidence of him using so-called "dark magic" when he's fighting, even when he's faced with potential death. Or her mind might open to the Force as they fight and she sees what he's actually teaching. Or Marisa actually reads the books while Gryph and Reimu are fighting and tells her she's fretting over nothing. Or several other possibilities I haven't thought of.

Plus it's more Touhou, especially in the later mainline games, that Reimu wins the spellcard battle against even the final and extra bosses and thwarts their immediate schemes, yet doesn't or can't stop the social change they're bringing to Gensokyo.

Also, here the fact that he drank more than anyone else and still didn't wake up with a hangover feels kind of like an unnecessary victory lap.

Probably that part has colored my perception of the remainder of the story. I note that the part of the Paris trip we haven't seen yet has gone without major incident, and that Sakuya apparently doesn't feel the need to Lens him status reports. I had kind of expected some sort of shit to hit the fan in Paris on the Friday night of the new moon, but it really would be far more inconvenient for him (and thus convenient for drama) for it to happen while he's off saving the Hyperion.

TL;DR: No fight and no explanation make Zemyla a sad enby.