The original storyline featured only five primary characters: Luffy, Zoro, Nami, Sanji, and Usopp. The filmmakers of this film made much of Franky and Robin's appearance, but most viewers are aware that they don't actually join the Straw Hats until much later. Now that those two were involved, I thought it would be fascinating to observe how the adjustments would be made!
Naturally, I watched the film, and despite my excitement, it was nothing like I had anticipated. Although they weren't even the "Main" characters in the film, Franky and Robin were present but didn't really do much.
There isn't much to see here if you have already watched One Piece. In a nutshell, episodes 78 through 91 are simply packed into two hours while Franky and Robin remain in the background.
That in no way implies that it was a terrible thing. Though there wasn't really anything new, I still enjoyed seeing it. With the exception of the very end. Alright, who is everyone's favorite "bad guy" from the anime, Wapol? It turns out that this film features a character by the name of Mushul, his brother. And that's the point of differentiation. Instead of only taking on Wapol, Luffy also needs to take down Mushul. Which, despite being brief, is actually quite an amazing fight.