it's a grayscale screen which supports only 4 shades of grey, as far as i know
the result will be horrible
While the LCD itself only supports 4 colors (black, white and two shades of grey) the greyscale library allows much more "colors". I tried Elephants Dream on my Mini and the result is quite nice -- don't expect it to be comparable to a color display though.
Btw, even on m:robe100 (which doesn't even have greyscales) you can actually watch the video. I wouldn't want it for serious watching though.