With the loss of Ace heavy in his heart, Luffy remembers the first encounter he had with Ace - and how he started his journey following in his brother's footsteps, all the way until the fateful day that Ace was killed. — FUNimation
The scene of when Luffy met Ace has been animated once before in the anime, but this is the completed version of those events. In the original animated version, Ace was sitting in a tree. In this episode, he's sitting on a boulder.
Curly Dadan's first anime appearance was in the Strong World Episode 0 Special. This episode is her first full appearance.