Why does the artwork change in naruto episode 30 and 71,both episodes are action packed with a differnt style?

Question

Both episodes have intense action but seem to have a more darker and blury feel.

Answer 1

well, for the artists, it's considered "better". Anime ALWAYS change their art style very later on. if u think about it, yugioh has diff art in every episode- very messy. try to pay attention to every anime u see, then u know what i mean.

Answer 2

it's when intense action fights happen. they did it when Naruto and Kiba fought.