Download the file and unzip it in a directory you want - i used c:\hexen2. Start visual CXX (whatever version, it compiles under vc6 and is said to also work on vc5.XX)
Browse to the directory where you unzipped the source. Select the H2MP dir if you want to compile the exe for the missionpack, otherwise select the H2W dir. I use the missionpack dir.
While in the missionpack dir, select the /code dir and choose the winquake.dsw file (sounds familiar huh?) Followed by that it will ask for the hcode.dsp file which can be found it the /code/hdcode dir. Select that file and select OK. If you are using any other visualc version then Raven used to compile it will ask to convert the project for you. Press yes.
it should be loading now (i got some visualc safesource msg's but it's advisable to cancel those).
When it's loaded, select build(in visaulc) and select "Set active configurations". I selected the "winquake - Win32 GL Release" here, but other configurations will also compile. Gl is for the gl version, the other "normal" one is for software and the hcode is the game source. I don't know what the PR release is. (don't compile yet)
You should also have the ml.exe file to compile the ASM code. This is from microsoft. If there is no ml.exe in the bin directory, of your VC install, then download the file at http://www.microsoft.com/ddk/download/98/BINS_DDK.EXE. Run it and it will extract bins_ddk.cab. Use Winzip to open this file and extract the file "bin_win98_ml.exe" from it. You shouldn't need any other files from it. Rename the file to ml.exe and put it in the bin directory of your VC install.
Now go to that dir and edit the progs.src file. On top there's a line which says:
Now you can press compile and compile whatever version you use. It'll give some warnings in Vc6, but it seems to work =)
You can now also open the H2W project and compile the other standard hexen2 exe (without mission pack). If you followed the above things good, there should be no problem in compiling them.Have fun editing, once i get hexen2 myself i'll see if there's something cool to change =)