Phew - well, for me it would be too dark. A bit like a haunted house.
As I said, I find the tiles pretty great, but not in such a large amount. I probably would have only extended the tiles on the side of the washbasin high enough to prevent splashes when washing hands and at the toilet only up to the bottom of the casing. Also, the white toilet kind of stands out too much. If there were still a white wall above it, I would personally find it more harmonious. But that's a matter of taste. At least the toilet is not run-of-the-mill and very original.