Everything except the animation was mid at best.
The characters felt bland, some felt like cardboard cutouts copied from the authors earlier work Durarara, splashed over with some steampunk watercolour. Noone felt very real except maybe the two cartographers.
The plot was just very predictable and didn't amount to much of a surprise. There was no twist. The one twist they had wasn't much of a twist, maybe for those who slept through the middle of the movie.
The solution to the problem that they created, the obstacle for the good guys, was also very bad, and it felt really disconnected from the rest.
The worldbuilding was rather intresting, but nothing that blows your mind. Your usual industrial steampunk japan pre ww2 vibe. If anything they focused to much on the worldbuilding and too little on the characters. It really felt as if the creator had this beautiful world in mind, but nothing that happened in it, so he did his worst at making a story and got someone to make a film out of it so he could look at it at home and smile at his worldbuilding.
I like the animation style though. It has some nice shots that maybe could serve as a screen saver. But since the characters are so bad its mostly just a long beautiful painting.