How do I unlock all of the movies?
You need an "S" on every level to unlock all the movies. Basicly to get an S you need to get all gold medals (painting trees, freeing graydians, destroying Ink things), all styles in the level and all the little color floating things for higher points.
Source: http://www.gamefly.com/answers/questions/view/15152-How-do-I-unlock-the-last-two-videos-in-De-Blob-2-s-extras-section