I'm something of an Oz geek, which is an eternally frustrating pursuit, knowing that 90% of the world is always going to think you mean Judy Garland singing "Over the Rainbow," and that public domain laws mean that we'll never see a movie series as faithful as the treatment Harry Potter got, simply because nobody can own proprietary rights. L. Frank Baum's world is ripe for further exploration, but instead everyone wants to do a "take" on it. Sci-fi Oz. "Realistic" Oz. Delusional Oz.
The Steam Engines of Oz is steampunk Oz, but unique in that it also purports to be a sequel, which brings us to ask: a sequel to which version, exactly? The green-skinned witches in black hats suggest an answer...until we learn that their mother was "Mombi, the Wicked Witch of the West." That's a combination of two different characters I hadn't heard made before - the movie Return to Oz controversially combined Mombi with Princess Langwidere, but elsewhere she's always been a much more distinct witch, firmly in the old hag mode.
This isn't the first Steam Engines of Oz collection, so I'm missing something, but what I gather is that at some point, the Iron Giant-like Tin Man became an evil ruler of Oz, and has since reformed, though bad blood remains with the Cowardly Lion and his pride, who are all gigantic, humanoid and dressed like Lobo. The former Wizard, Oscar, seeks his twin nephews, the witch twins seek revenge, and the search is on for Ozma's true heir. Also one of our heroes is a blue-haired punkette with a nose-ring and a corset, just because.
And there's a mecha-Cthulhu. Because of course that's totally something that belongs in the land of Oz.
Maybe I'd have less of a problem if this weren't trying to actively build on Oz continuity - when the very first frame of your comic is people standing in the deadly desert (which would turn them to dust in any other iteration), I feel like the writers, Erik Hendrix and Sean Patrick O'Reilly, don't quite get it. If you want to do an anime-like take that culminates, as this does, in battles with giant robots and people flinging balls of energy at each other, fine. If you want Mombi to be the only witch, also fine. Just don't tell me it's Baum's universe. Give me a new origin story so I'm not hung up on my old one, which conflicts with the movie version of the old one that you may in fact be using instead of the book one.
That aside, how does this stand on its own? The storytelling's a bit awkward at first, with speech bubbles and images feeling a little haphazard in their placement. Once it got to Ozma and Jack Pumpkinhead, though, the story took a fun turn and I liked the new spin on those characters, suitably rooted in canon but with a new spin. I didn't care for the reinterpreted lions, nor quite understand the point of the wizard's nephews - the story has altogether too many characters, and one of them's named "Gromit."
Mecha-Cthulhu was just weird, as were the airplanes that suddenly appeared to fight it (airplanes against a giant monster? Where'd they get that idea?). Oz shouldn't be about huge battles anyway - the idea in the books is that no-one can die, so struggles have to be creative (if somebody ever decides to do Oz of the Living Dead, I'll try to be as open as Cummins was to Afterlife With Archie - provided they use classic canon as a starting point). Despite the occasional glimmer of a good idea (the Ozma bits), I wouldn't really use the c-word much here. This was Kickstarter-funded, and I suspect the funds didn't go towards much copy-editing (why would they - that'd be low on my priority list with a limited budget too) - ultimately, I just hope the fans who paid for it ended up getting something they liked.