Nice set of images with a pleasant monochrome drama.
I have one of these lenses(ZF 21mm), and while the general image forming qualities are superb, the one thing that haunts me about it is the distortion. I believe it adds a subtle and undesirable tension to the photograph, even if there are no straight lines to detect it from.
By the way, my former Nikkor 20/2.8 Ais had even worse wave distortion that the Zeiss 21.
The elimination of the large back focal distance in the mirrorless cameras has facilitated a reduction in wide-angle lens distortion that is immediately noticeable.