I don't find that purple at all, just vivid and precise. It's evocative yet still clear.

My only objection to gruesome is it seems oddly judgemental. Dreadful, maybe? Not all German units were as, well, barbaric as the Mongols.

I'm pretty sure not all Mongols were as barbaric as the Mongols, just like not all Germans were as barbaric as the Germans. People are both shit and mundane like that. I figure they deserve standing up for as much as Germany, don't they?

Then it is misleading and unclear. Does this make the point clearer?

Mongols riding war elephants and Germans riding Panzers streaked overhead, enslaved dead traveling to carry out gruesome missions.

I think you can leave out "they despised." Enslaved carries the connotation of having no say in matters.

Cool, edited to reflect that. So it is now clear that is the *missions* that are gruesome and that those carrying it out have no choice? I used Panzers and elephants because the mixture gives an exotic impression. It could be Toussaint Louverture or someone as heroic as you care to mention. They would still be sent by on gruesome missions.

I like the Panzers and elephants--did the Mongols use war elephants? I thought they were all about the horses. Or is that part of the point?

Typo, it's hard to judge based on the world-building and one paragraph. What is the actual story about? Who is the protagonist?

As Jill cycled down the street spectral carriages flashed above her. Clouds showed faintly through the ornate trimmings and fire-breathing horses as they pulled their loads to destinations across town or across the world. Mongols riding war elephants and Germans riding Panzers streaked overhead, traveling to carry out gruesome missions. Though it was only two in the afternoon, blue lights flickered in every building. All houses were haunted now.

I know this is the original paragraph, but I wanted to question the last line. The fact that all houses are haunted now is something that anyone living in that world would know, so it's not something they would remark on. Even a reader who scanned the cover copy would know that -- it's better to show that, with specifics, than to paint a broad picture.

I'd also suggest you focus on the perspective. You mention Jill, so it could be third person, but it sounds a little omniscient as written.

Thanks for the useful feedback Amy.

One general question. This will be my first novel. Generally in terms of asking for betas, is it customary to seek beta readers as soon as a few chapters are done? Or is it more usual to wait until a draft of the entire work is complete?

Deb Grabien asks for betas chapter by chapter.

Great. My process is going to be a bit Tolkein like. I'm going to start by writing a history of my world, or rather of how our world was turned into this one. That won't be in anyway publishable. But in the course of doing that I think I will find my viewpoint character and the story that will take place within that history. I'm going to refer to this as "finding my hobbit". Once I have found I my hobbit I will begin writing actual chapters, probably after writing a really short outline. Plus I hope that there will chunks of the history that I will be able to steal from for the book.

The reason for this process is that, as Amy spotted, I don't really have a plot or a character. I have a world and pretty much the whole history of the world. So I hope if I write that history down, even though the result won't be publishable, or anything I'll want to share, I'll be able to find a good story to tell within that world.