The only thing that comes to mind is maybe soundrts?  Have you taken a look at how that's done?  Though that's an rts and not a tycoon game, so maybe it won't help out that much, but that's all that comes to mind at the moment.  Their are other sighted devs on here like Aprone, maybe he can offer better input?

Tiles are the easiest way.
I feel like the zoom idea should work, but AFAIK no one has implemented it.

Hi.
aah a newby
Well first there are a lot of libraries that can handle your screen reader.
One such is tolque which is opensource.
There are others some written by others here I forgot their names.
These handle the most popular screen readers, jaws, window eyes, supernova dolphin and non visual desktop access, nvda as well as sapi interfaces.
It may be better for you to directly interface with one of these libraries for screen reader control, so you don't have to spend time busting your gut with every interface.
Ofcause depending on what it is you can go the entire hog with full voice guidence via recorded files which will increase your game size a lot.
As long as you can support 2 or 3d audio with sounds from directions, music to sute moods and changes as well as sounds for events and the like well thats about it.
Some way to locate objects, and some way  to locate walls where needed as well as target.
Some older games had target beeps but there are a lot of things you can do with panning and the like.
We can and have got a lot of actual audio games with the right environment we can make complex games.
I am not sure of roge likes but if you go to mush-z.com for example and download and install the sound pack then rummage through the folders there is music for every battle, condition, movement environment and the like.
There are event sounds and the like.
Look at some of the oldergames on gmagames.com, some of the japanese games with sounds, then look at audiogamehub at audiogamehub.com
Sorry users I shouldn't plug myself but I kinda work for a company now so yeah.
Look at eurofly, finally look at either kitchensinc.net, or spoonbill software and agarchive.net for audio games.
Finally look at ffproject.com and choiceofgames.com, for text stuff.
And if that is not enough there are all the old text adventure languages and then there are the newer ones like twine, which you can make using their site or via download of it so there you go.
I hope that helps you some.

Wouldn't you want a z-axis?  Or is your y-axis your z-axis?  Not sure how you could represent that, and maybe I'm wrong, but just something I thought of while reading your post.

You guys have given me some great stuff to get started with, and the idea of actually trying a few makes a lot of sense. Thank you for your suggestions.

I also think it'll be fun to do some experimenting with. Questioning whether I want to modify an old roguelike I made, or come up with something new to play with.

Re 3D - I think it helps at least that railroad and 'space management' (think Theme Hospital) games (the kind I'm interested and curious in) tend to be largely 2D, or 2D with levels occasionally - so I don't think completely impossible... I hope!

I didn't realise that there was such a thing as a screen reader library. My assumption was that I was going to try to make something work in a console, as that should be easy for a reader - but I'll have more of a think. Other libraries and tools mentioned here are stuff I've never heard of, so I'll have to spend some time and figure them out and what already exists.

Is this forum welcoming of experiments and attempts for feedback? Or should I try to hold back until I have something more finished?

Thanks again,

L.