MIchael Arias’s 2006 adaptation of Taiyo Matsumoto’s Tekkonkinkreet was released 12 years after the completion of the manga and, while imbued with a great respect for the source material, changes the visual style dramatically.
Arias, in interviews and the anime’s audio commentary, credits the Fernando Meirelles film City of God and its scenes filmed in Rio De Janeiro using handheld camcorders with providing much of the visual and stylistic inspiration. Arias’s Tekkonkinkreet visually translates Taiyo Matsumoto’s complex, black and white, two-dimensional images into an urban-baroque, colour saturated and kinetic film.
In order to mimic the style and pace of live action filming the production team at Studio 4°C created out of focus images and blurred visual effects. In chase scenes the “camera” pans about wildly and changes of perspective are often executed in wide, sweeping panoramic shots. Visual conventions that are typical of live action are introduced as constructs that, while existing separately from the actual process of animation, are an intuitive part of visual film language.
The decision to represent Treasure Town as awash in color further distances the anime from Matsumoto’s original but, while the anime is colorful, there isn’t a pop, reductionist approach to the palette. The color used is rich and subtle and meant to further communicate the faded glamour of Treasure Town.
As Arias stated in a interview with Otaku USA in 2007 “Matsumoto’s artwork is fantastic, revolutionary even. But I wanted to do something that that was three-dimensional and felt as solid as the world outside your window. I wanted to make it feel like a documentary shot inside a hand-drawn, handpainted world. And I don’t think just taking Matusmoto’s style of artwork—black lines on white paper—and just filling in colors would be enough.” 
Studio 4°C attracted a number of very talented contributors to this project including art director Shinji Kimura, who won “Best Art Direction” 2007 Tokyo International Anime Fair for his work on Tekkonkinkreet, and animation supervisor Shojiro Nishimi.
This wonderful article in Pingmag provides great insight into the team behind the anime and their work process.
Mainichi Film Awards – Best Film Award, 2006
Museum of Modern Art’s Artforum magazine – Number 1 film of 2006
Tokyo International Anime Fair – ‘best original story’ and ‘best art direction’, 2008
Media: Tekkonkinkreet opening sequence (thanks to BleachMan954) [copyright 2007 by Sony Pictures]
Images: screen captures from Tekkonkinkreet, anime [copyright 2007 by Sony Pictures]
 Alt, Matt (2007-10-17). As Immersive as Possible: The Michael Arias Interview. Otaku USA. Retrieved on 2008-10-26.