The story of Rurouni Kenshin can basically be split into three arcs. The first arc—with Kenshin meeting Kaoru, Sano, and the rest of his new friends—is about Kenshin discovering that, despite his bloody history, he still has the chance for a happy, normal life. The second arc, Shishio's rebellion, is about Kenshin dealing with the unintended consequences of abandoning his place in the revolution when he did.
However, the final arc, as seen in this film, is about the personal toll of Kenshin's actions during the revolution. While Kenshin may be considered a hero to those who fought alongside him, the simple fact is that he caused a lot of hurt and pain as the Battousai—and not just to the targets he so mercilessly cut down. Just because he has stopped killing and now desires nothing more than a peaceful life with those he loves, that doesn't mean his sins are simply washed away.
The Final is centered around the theme of “human judgment” (in contrast to that of “divine judgment”). While god may choose to punish or forgive Kenshin's sins when he dies, that is of no concern to the victims of his crimes. They have judged him guilty and they are coming for their revenge—to make him suffer as they have. The foremost among them is the film's main antagonist, Enishi.
Enishi is a fantastic villain—and one quite unlike the ones Kenshin has faced so far. Not only is he younger, faster, and stronger, but smarter and better-trained as well. Yet, he's not some megalomaniacal baddie, nor is he looking for the glory of slaying Kenshin he can gloat about being the best. (In fact, he doesn't care who kills Kenshin as long as he's dead in the end.) Nor does he have some kind of grand ideology and complex plan to take over the country.
All Enishi wants is for Kenshin to feel the same pain he has—to have the things he loves taken away one by one—knowing that there is nothing he can do to stop it. Moreover, he wants Kenshin to know why this is happening and who is doing it to him, and that he deserves it for all the pain he has caused.
Thus the question of the movie becomes: “How do you beat a person focused solely on destroying everything good in your life—a person superior to you in every way and with nothing to lose?”
Overall, The Final is a relatively loose adaptation of the source material. While it has the same antagonist, themes, and basic story structure, it is largely its own story—which is probably for the best. In the original Rurouni Kenshin manga, this arc took 10 full volumes to cover. (The previous arc, which got two films dedicated to it, took 11.) Trying to cram all this into a single film would have been a fool's errand, even with the extended flashback sequence being separated into its own film later this year.
Of course, while it is undoubtedly a better film for all its cuts and rewrites, that doesn't mean that aspects of the story don't take a major hit. The villains, except for Enishi himself, lose nearly all of their character development—with some being replaced completely.
The main heroes' characterization also suffers from having their roles changed and downplayed. Without a doubt, the person who gets the shortest end of the stick is Yahiko. He no longer has any noticeable character arc or effect on the story. On the other hand, while Sano serves as the story's punching bag, the sheer amount of damage he takes without going down makes him feel like the most badass character in the film.
Interestingly, it is the side characters from past films that really get a chance to shine, namely Misao, Seta, and Aoishi. Even “Sword Hunter” Cho returns for a sizable supporting role in this film.
When it comes to the music, it's on par with the past films in the series—up to and including a new J-Rock theme song by ONE OK ROCK. However, the best use of music in the film is the total lack of it in the final battle between Kenshin and Enishi, which codes the battle as a tragedy instead of a triumph.
Visually, the film is wonderful. The fights are masterpieces of choreographed combat with little-to-no CG to be found. The wire-fu is used in just the right amount to make our heroes and villains seem superhuman but not cartoonish. If you enjoy practical effects, you're going to love the care and attention that went into them in this film.
All in all, this movie is best for people who haven't read the manga. It's in no way a bad film, but the cuts and rewrites needed to fit the story into its 2-hour and 18-minute runtime make it nearly unrecognizable to people who were hoping to see the manga brought to life. Of course, if you're fine with seeing Enishi's story in a new way, this movie is a ton of fun. And if nothing else, I can promise you that the fight scenes don't disappoint.