-I think the movement is due to the shadowing that isnt universal but instead dependant on a light source. Because of this when a character moves and objects and setting interfere with a light source it is immedeatly reflected in the characters shadowing. for example, when the main character hoped out of the car and started walking down the sidewalk the sun was the light source and it was apparent that it came from the top near the right side of the screen because the light reflected not only on his right side but stronger shades of light orange and yellow on his shirt where the light source would be concentrated the most, like the rounded shape of his shoulder. And when the character began to move he walked under a tree and the concentration of light in many spots changed rapidly as he passed under the branches and leaves.
-I think many more options are opened for making a movie when animation is used instead of actors. The art work is a little surreal and off balanced so I have to think that this sketchy look is something the makers of the movie were trying to acheive but didnt think they could get this akward effect any other way. The movie a Scanner Darkly, for example, has a very surreal and almost sickening look to it and i think they used animation to create this look based on the plot that revolves around drug use and the effects of. I think they intentionaly utelized the effects of animation to create the feeling that is vague on detail and hazy like a high. Without animation that movie might have not been able to create the same disorienting effect.
