Having just reached the end of Episode 15, I have to say I'm very impressed with the game as it is so far, although I probably missed a lot of stuff due to playing blindly.
It appeals to my need for a challenge quite nicely, I really wished I'd actually EV trained properly to alleviate the challenge somewhat.
The only Leader I'd really struggled with was Serra; I had to actually backtrack all the way back to the abandoned Power Plant and prepare a Magneton, which completed floored her.
Fighting Cal on Apophyll Volcano made me train a Camerupt just for that fight too. Although to be fair, Noctowl was garbage and Hustle Raticate missed WAY too many times for me to keep him.
I really liked the new shiny skins, got to see a number of them during my streams of the game. Roserade was probably my personal favourite, followed by Lopunny, of the ones I saw.
The music in general was really nice, I liked the Gym Leader battle theme a lot, made you really pumped for the challenge. I also liked Jasper Ward's overworld theme for some reason, it just resonated with me.
Most of the field effects were manageable with my team as it was, but a couple of them were absolutely brutal. Like Serra's Mirror gimmick, Corey's auto-double Venoshock with Crobat, and the Circus arena for mainly the Fighting portion.
Big fan of the Glitch Field, it's definitely one of my favourites, having played Gen 1 competitively. Very interesting use of Draco Meteor, might I add.
I'll add more thoughts as I think of them.