Alright, just watched the episode and I have some thoughts as a source reader. I will make sure to not spoil things.
Firstly, I liked the Delta bit, but ultimately felt like it could have been shortened to give some more time to the Alpha fight. It was executed a bit differently here where they actually fight a little bit. In the source, they have a standoff, but before any blows are exchanged she already can tell its Cid. In fact, the hair that Shadow Garden finds at the scene is from Cid grabbing Delta's tail to prevent her from running back to Alpha. The way they did it here created drama, but I felt the time they devoted to the fight and follow up could have been better spent on the Alpha confrontation. Speaking of...
The Alpha fight. This confrontation is really the emotional climax of the arc. There were some key elements of this sequence that seem to have been cut for time. When this season started I had hoped that this fight was going to get a glow up the way that the climactic fight to end season 1 was. However, it was over very quickly. Credit to Alpha's VA though for getting across the anguish and despair that she is feeling in that moment. The figure that she sees as something like a deity basically tells her that she is no longer needed and literally casts her aside. That has to suck.
Moving on, the Iris/Alexia scene is an anime original and I really like it. The scene does a good job of keeping Alexia in the story and demonstrating her character growth (and a fetch new hairstyle).
LN Vol. 5, 6 Spoilers
Also, it foreshadows the turn that Iris does to the cult and how Alexia strives to better understand the events that are happening in the world of the shadows. I really like the idea that Alexia feels driven not only to improve her sword, but also her mind and understanding of the world she lives in.
The rest of the episode was pretty similar with only some minor changes. If you didn't catch it, Cid actually foreshadowed saving Yukime from Gettan as a child back in season 1. In the scene in which Rose killed her father and relays her story about how the "Stylish Bandit Slayer" saved her life, Cid wondered to himself, "I thought that was a therianthrope girl". The event he was referencing at that moment was his saving of a young Yukime. The two events seem to be hazy, vaguely similar memories in his mind. He was just too focused on other things at the time I guess.