Quick update. I checked the internet for the RtlFreeHeap issue.
It seems to be related to the NT Native API. It has to do with the PE loader, too, I think.
Windows 9x doesn't seem to be affected. Well, Windows 95, at least. Windows 98 was the first one to incorporate parts of the NT kernal.
"NTKERN.VXD is the emulator of the NT/WDM kernel over the old 3.x/95/98/Me Windows VMM kernel."
https://community.osr.com/discussion/143623/n … xd-windows-2003

Edit: I forgot to mention: I also forgot to change the Win32 project type from Debug to Release when I made the test binaries.
So it wasn't unlikely that all those debug information might have been too much for Win32s.
However, that wasn't the case. After changing the active project to Release, the file just got smaller. The error remained.

Edit: I hope you don't mind for the many dilettante mistakes of mine. 😅
I've been a modest tinkerer all my life, always learning by doing. 😄
So please bear with me. Please rather see this thread as a brainstorming session, sort of.

I see alot of choices here on getting a project up and running. I wouldn't mind trying to get one of these old compilers going, but right now I am hoping for a cross compiler on my modern machine to do the job, as I've had pretty good success at that. I think it will prove to be difficult still, and I might want to try VC4 or VC5 for win32s. Although again I think gcc with linking to glibc instead would be a good choice, as SDL isn't really all that specific to Microsoft's C libs. SDL should be able to work without msvcrt pretty easily.

I like the SDL idea, since it might prove to be a lightweight example on how to do things, to get you to the point of wanting to wrap DirectDraw to something else.

So I think to carefully think through to pick and try things will take me some time.