One Piece hits an interesting episode here as it's all about the action for the most part, but there aren't any really big moments here that defines it. It's instead about the smaller fights, the basic back and forth material with a few revelations along the way to give it a little more impact. On the positive side, there is a whole lot of action here and various forces are coming together more and more. On the downside though, it feels like a placeholder episode to just push everyone along a little bit more.
With so many characters moving about in here, nobody gets any full on time. The largest block of time that's spent is between Luffy and Blackbeard as the two start in on fighting with each other, though Luffy just wants to get past him so he can reach the surface. Blackbeard's an interesting character since I'm unfamiliar with his past for the most part, so seeing the flashback scenes where he and Luffy met before, with Luffy not knowing who he is, is definitely welcome as it helps to flesh him out. And it's been several years as well probably since he was seen in some of these flashbacks. What's really fun about Blackbeard is that we learn what his special power is and why he's such a threat to the Devil Fruit users. I'm halfway surprised we haven't seen another character with this ability before, but if not then it shows the kind of planning that's gone into the franchise overall and that's what keeps drawing you back to it.