I get a cryptic message suggesting I have the wrong version. Possibly I got the 64 bit version instead of the 32 bit version.

There is no 32-bit version. The game is 64-bit only (which is logical because you can't buy 32-bit x86-compatible CPUs for some time). Says on both GoG and Steam, requirements: Windows: XP / Vista / 7 / 8.1 / 10 (64 bit)

Thanks for the answer. It wasn't very obvious too me as most games that don't require more than 4 GB RAM still support 32 systems and my computer otherwise meets the minimum reqs. I guess I'll have to look into a linux dual boot option

--edit--
nvm the linux option. it seems my amd gpu isn't supported on linux :(

Doesn't start on xpx64 either. I have w7 boxes and it works there. My point if they say it works then make it work. Otherwise don't. Xp is less hassle then w7.

Are you sure? The german page of Numenera’s Immortal Edition at GOG says
"Läuft auf:
Windows (XP, Vista, 7, 8, 10), Mac OS X (10.9+) und Linux (Ubuntu 14.04, Ubuntu 16.04) "
(läuft auf = runs on)
without mentioning 64 bit there.

Only a bit more down the page it reads

"Mindestsystemanforderungen - Windows: XP / Vista / 7 / 8.1 / 10 (64 bit)"

So with the first line not mentioning 64 bit at all, I understood the "(64 bit)" to belong only to the Windows 10 mentioned last...?

Edit: Especially with the other requirements, such as 4 GB RAM or Direct X 9.0c which both can be fulfilled even by 32 bit Windows XP...?

1) It means 64-bit for all mentioned Windows version. Applying 64-bit to just the last in the list doesn't make sense.

2) 32-bit Windowses put limitation on amount of memory a process can use. Default theoretical maximum is 2 GB of addresses per process. The entire address space on 32-bit Windows (any version) is 4 GB (regardless of how much physical RAM you have), and by default it splits it to 2 GB for user processes and 2 GB for kernel. It can be tweaked to 3 GB for user processes and 1 GB for kernel, but it can compromise system stability in case of too many device drivers being loaded at the same time.

The idea behind 64-bit requirement is that you don't have such limitation anymore. If you have 16 GB of RAM, the game may use as much as it can until it compromises RAM for kernel. 4 GB RAM is theoretical requirement for running the game on low details on low-end machines, but if you have more and want everything on max, 64-bit Windows doesn't prevent you to do it.

(More info for the sake of completeness: 32-bit application running on 64-bit Windows can use up to 4 GB of addresses if compiled with "large address aware" flag, but if run on 32-bit Windows, 2 GB limit still applies, and you cannot go beyond 4 GB even if running it on 64-bit Windows).

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