The heavy blacks and absence of any shading create a very dramatic look and add a sense of forboding that fits this particular incarnation of the Doctor.
My only criticism is that I don't like how small the Dalek seems next to the Doctor himself. But that may be a perspective thing.
Source: DeviantArt — War Doctor
Doctor Who Fan Art — The War Doctor by Eoghann Irving, unless otherwise expressly stated, is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.