It kind of reminds me of that old Borland Museum that had the old Turbo languages for free download. http://edn.embarcadero.com/museum
Sadly they stopped releasing old versions in 2005. I had hoped there to be a Delphi 1.0 release. I actually got Delphi 1.0 on a magazine CD-ROM from some UK magazine I bought, and then forgot where I placed it. I used to program in Delphi 1.0 and 2.0 I still got my 2.0 book and how to make code Y2K compatible in it.
I got old Visual BASIC versions as well.
It seems this is the Wolf3D source code without the data files so you have to use the shareware version of Wolf3D or Spear or buy the commercial versions.
It is written for 16 bit code for DOS, so converting it to 32 bits won't work. They had to use a lot of tricks for 386 and under machines just to get it to work in 3D mode. 486+ machines run it better but at a certain level it does not scale very well.
Basically it was a f*-it by ID, just release the code for the LULZ, throw on a commercial license to limit use, and then see what happens to it.