I will divide this episode in three based by the plot.
1. Violence and gore
This part is so good, that its unsettles you to the core. Shakes your feelings, grasps you and makes you feel as bad as the characters in it, keeping you on the edge of your seat. Shocking and truly gruesome . It is so phenomenal that you have mixed feelings- cant decide if it was so bad because it made you feel so disturbed, agog and uncomfortable or is it remarkable exactly because of it.
2. Emotions
This part gets you all in your feelings. After a very emotinal and sad parting, it amazes with a badass action and leaves you bittersweet in the end. That mid credit scene shows you the whole different side of the story.
3. Endgame (yes Avengers inspired me in this one)
"So...what now?" Well, this part anwers to all of your questions. It feels like an intro to next episode, which gives off a feeling of a grand finale even though there are 3 more episodes. The boss battle is approaching, as we see our 3 main parties in the war and whats left of them. Just one word: EPIC. The very ending leaves you completely crazy, cheering for the next episode.
May be one of the best anime episodes i've ever watched. Truly a masterpiece.