Thanks to Justin White for this one: Unreal Tournament running under NT 3.51!

Reportedly all it needed to run was IMM32.DLL

Wow, that Xerox Alto emulator runs under NT 3.51!

And more applications running where you might not expect them:: OS/2 1.x *NATIVE* ports of the Windows 3.0 applications under OS/2 1.3!

Unlike OS/2 2.x that can run Windows 3.x in a VDM, or OSes that supported different "personalities", these are native 16-bit OS/2 1.x binaries. These applications were provided to demonstrate the WLO application porting library from Microsoft. With WLO, a developer could recompile their Windows 3 applications for OS/2 with minimal changes.

This almost makes OS/2 feel like an early Windows NT, but these libraries were a separate effort from NT.

It is interesting to consider how many times the Windows 3.x applications have been around the block:
16-bit Windows, ported to OS/2 1.x, ported to 32-bit NT x86, MIPS, PPC, and Alpha, run under OS/2 2.x VDMs, run under NT VDMs, run under DeskViewX VDMs, run under WABI, and probably more that I can't think of right now.

Portability was the name of the game back then.

The libraries were provided after Microsoft and IBM "broke up" and started pushing developers towards Windows instead of OS/2.

BTW, if anyone ever comes across the 0.9 beta of WLO, I would like to know. It was publicly distributed, but the only trace I can find of it now is a listing of a long defunct FTP site:

   WLO09.ZIP      Version 0.9 pre-release of Microsoft WLO libraries.
   WLOINF.ZIP     Information about WLO
   WLOAPP1.ZIP    Windows Applets for use with WLO
   WLOAPP2.ZIP    More Windows Applets for use with WLO.
                    All above Free WLO demo from Microsoft

The WLO10 archive shown above can be found at many OS/2 related sites.