I must admit, I do like this alot! However, the background with the sky doesn't look right, instead of looking like any form or sort of sky, clouds, or pullution, it looks more like blurs of color and little else. The background structures are also simply done, they are merely colored silhouttes. That and the machine-beast uses many of the same rusty colors over and over with little variation other than shading, even though it is implied as rusty, and rust is differently colored for different metals.
Oh but my nit-picking does not change that this is still incredible and well done!