Mamoru Oshii's (Tenshi no Tamago, Patlabor 2, Sky Crawlers, Tachiguishi Retsuden) Innocence is without a doubt one of the trickiest accomplishments of his already rich and challenging career. From the get go the film was doomed to fail, back then it simply seemed impossible for a sequel to live up to the standard of its predecessor (Kokaku Kidotai). But Oshii persevered and created what would become another benchmark in Japanese animation.
To me Innocence is the perfect sequel. It's everything a good sequel should be, while at the same time avoiding all the predictable traps so many other sequels fall victim to. It's a film that respectfully refers to its predecessor but stands well on its own. It shares the same perks as Kokaku Kidotai, but at the same time it offers a different set of challenges. Oshii perfectly balances the levels of homage and improvement, marking Innocence as the best sequel I've ever laid my eyes on.
Still, not everyone is bound to be happy with some of the changes Oshii made. While you often hear people complain that sequels copy too much from the original, every change made might take away from the experience fans are aiming to relive. Personally I believe that most changes in Innocence are actually improvements over the original, but that's a very personal statement and your mileage may vary. One thing is certain though: Innocence is a unique experience that deserves to be valued on its own merits (though it's impossible to not compare it to the original).
The first major change lies with the story and its main characters. Innocence completely abandons the adventures of Kusanagi (though she does appear in the film), instead Oshii puts the focus on Batou and Togusa. With Kusanagi lost in the wired, Batou is coupled with Togusa and they continue their work for section 9 together. The story for Innocence isn't truly original though, it's an re-imagined version of a chapter Oshii skipped when he made the first adaptation of the manga, cleverly rewritten to appear after the events that unfolded at the end of Kokaku Kidotai. Innocence is not really about the actual storyline though (it's little more than an expanded SAC episode - introduction of case/detective work/finale), but about the concepts Oshii links and refers to in between the dry plot points.
Where Kokaku Kidotai approached the human-machine debate from a human perspective, Innocence comes at it from the other way around. Innocence talks about dolls and other inanimate objects and ponders how far their souls might stretch. On top of that Oshii claims that Innocence is his most romantic film, focusing on human-machine, human-human and human-dog (it's an Oshii film, right) relationships. While his claim is factually true, it's probably fair to say you shouldn't expect anything traditionally romantic from Innocence.
When Kokaku Kidotai was first released it immediately became a visual benchmark for other anime films to compare themselves to. At the time it seemed impossible for Innocence to match the impact of the original, but it actually managed to go beyond. To date, Innocence is still a true (audio)visual masterpiece, both on a technical and aesthetic level. The amount of detail is simply stunning: background scenery and settings are incredibly rich in detail, the character animation is spot on, the camera work agile and innovative and the interaction between environment and characters often surprising. Oshii developed a perfect blend of CG and traditional animation (without the typical cell-shading look) that looks stunning on both accounts. Not all CG is perfect of course, but the imperfections limit themselves to single shots, the rest of the film remains gobsmackingly beautiful. Favorite scene: the helicopter ride right before they arrive at Locus Solus.
The soundtrack is another strong example of how to pay homage to the original while still delivering a new experience. While some tracks are clearly reworks or re-imaginings from the original score (Kenji Kawai is once again responsible for the music), the overall effect of the score is quite different. A difference that is dominated by two very unique jazz tracks. While these are far from safe choices, they do fit the atmosphere of Innocence and help a great deal in establishing the unique atmosphere. On a technical note, all audio effects sound incredibly crisp an clear, adding to the strength of an already powerful soundtrack.
As to why I use quotes from many famous philosophers the answer to that is that I want to prove how unimportant the dialogs are to a movie. In GIS 2 you don't really have to listen to any of the dialog, it's just part of the many details in the movie and you don't have to pay any attention to a lot of the dialog in order to understand and appreciate the movie.
The biggest challenge of Innocence are the many quotes and references to external sources. Many people will struggle a great deal trying to comprehend everything that's being said and referenced. Which is exactly why Oshii's quote above is so important. It's a first-hand testament off Oshii himself, stating his ideas behind the use of the quotes: they are essentially little more than sonic triggers for atmosphere. The extra meaning they carry with them is nice, but not essential. You can ignore the meaning, but not their influence on the soundscape of the film. It's difficult though, people are so accustomed to text as information that it takes one or two extra viewings to see what Oshii really means with his statement. What helps is the superb voice acting (do make sure you watch the original Japanese dub), but it remains challenging to ignore those little white sentences on the bottom of your screen.
Despite its impact, Kokaku Kidotai was a rather timid film, Innocence is anything but timid. It's flashy, in your face and self-conscious. It's also incredibly pretentious, but it knows to live up to its own pretenses. Everything about Innocence is grand, nothing is compromised. It's clearly Oshii's film and Oshii's film alone.
If you ask me which film is better, I'll definitely go for Innocence. While it enjoyed a similar impact as the first film, it clearly benefits from budgetary and technical advantages, making it a more immersive and impressive experience all-round. If melancholy is your thing then Innocence loses without even a chance of a fair fight, but beyond that I don't really see how anyone could prefer the original to this film. It's Oshii's magnum opus and one of those rare occasions where a visionary director gets a (relatively) big budget (nothing compared to Pixar films of course but very expensive for a Japanese animation) and carte blanche to bring his vision to the screen.
Innocence is a cinematic celebration. It's an audiovisual delight, it's thematically sound and rich and it invites you to watch and enjoy it time and time again. It may prove to be challenging when the first time around you're trying to ignore the spitfire of dialogues and quotes, but if you just enjoy them on an emotional level, letting them become a part of the scenery and letting them sink in on a more subconscious level, you'll come to realize how important they are to the overall atmosphere of the film. Innocence is without a doubt one of my all-time favorites and definitely recommended. Make sure you've seen Kokaku Kidotai first though as it is essential to get the most out of Innocence.