I got all of the bonuses on the second disc in the VAMPYR set watched. They included a documentary made in 1966, a video essay on the film (very good), and a radio speech on simplicity in film delivered by Dreyer in 1958 (very dry and a bit dull).
Dreyer did say that in his estimation, color was completely misused in most color films made, and that there were only two or three color films that had ever used color correctly, the best being GATES OF HELL.