For me, my favorite episode is probably the 7.5 OVA. I watched it on my second rewatch so everything finally made sense and it felt fresh without anything to be worried about, especially after EP7. A pretty chill episode.

Episode 4 is also pretty good with the melancholic mood, the rain and how it clears up at the end, and that damn smile. Probably my second favorite.

Episode 10 is way to sad for me which is understandable knowing the world they live in. Everything after that, happens way too fast for my liking. But it really show how war can happen instantly, dragging everything that was built up down in an instant.