Asian studios have been trying to adapt manga/anime to live-action for decades. They all failed.
Finally, we can call all this pre-Rurouni Kenshin. The first movie had some flaws, some unbalance, but it ultimately delivered. Now, Kyoto Inferno is a great 2nd part leading the way to The Legend Ends.
The Shishio Makoto story-arc is super long in the manga. All the Juppongatana mini-story arcs were left behind because of that. This makes it possible to condense it to 2 movies.
So, do not expect deeper character development. The movie decided to focus on the very specific attempt to bring down the government and undo the Meiji Ishin (by the way, do read about it at Wikipedia, go look for the terms "Bakumatsu", "Meiji Restoration" and you will understand better the background about Sekigahara, Toba-Fushimi, and you will feel less lost in case you don't know Japanese History).
If you watched the anime or read the mangas (which I highly recommend), you will easily feel in the gaps with what you already know. The movie stitches together several memorable scenes from the source material.
Some parts had to be adapted, of course, and I think they did a good job, specially on how they fit the Oniwabanshu. Not sure how the Aoshi story-arc will fit in the next movie.
This movie had to remove several stuff from the source material in order not to look silly in a live-action, such as the special moves, screaming attacks ("Ryuutsuisen!"). But I'm most interested in how they will fit Kenshin's mentor of the Hiten Mitsurugi Ryu on the next movie (in the manga he will teach him the ultimate moves, Kuzuryuusen and Amakakeru Ryuu no Hirameki). He does show up very quickly so it's going to interesting how this unfolds.
The relationship of Kenshin and Kaoru, of course, had to be diluted to the bare minimum to give Kenshin the motivation to go forward (it was already diluted in the source material).
All in all, the filmography is superb, the casting is spot on, the story adaptation was very competent to compress a very complex source material.
If you're already a fan of the series, you will not be disappointed. If you're new to the series, this could motivate you to go read the original.