There are spoilers in this review, so don't read if that sort of thing bothers you.
What can I say? Meh. This is certainly harmless enough but I can't agree with the glowing reviews of others. I feel like it did NOT feel much like a Holmes story, except where the author just cribbed Doyle. The steampunk venue did nothing for me; it seemed like just an excuse to make extraneous changes: Sherlock Holmes is a motorcycle enthusiast! John Watson has a cannon where his arm should be! Mycroft is a woman! None of these adds anything to the Holmes mythos and none of them pay off in any particular way. Oh, and of course, there's a dirigible at one point and it crashes, as if to prove the story's steampunk credentials.
The weaving of the Jules Verne mythos (via Nemo) into the Holmes milieu has promised but never really contributes. The characters are flat and the known ones act out of character. Finally, it reads a bit more like an action movie than a Holmes story. There is gratuitous gun play and extraordinary violence for a Baker Street tale.
I was a supporter on Kickstarter and I retain some hope that, once the series finds its footing, it will excel. But this first entry was, to be blunt, disappointing.