This is the same as Blbej Den - Final, but its packed in a zip archive instead of an .exe installer and it also contains libraries for Linux version of Half-Life (It has the libs for Windows too). This is the English version.
Českou verzi lze stáhnout na karyk.cz/sw.html
To install, just unpack the archive to you Half-Life directory (where hl.sh or hl.exe is located). After starting/restarting Steam, Blbej Den will show up in your library among your other games.
You can find the location of your Half-Life directory on Steam - in your library right click on "Half-Life" and select "Properties->LOCAL FILES->BROWSE LOCAL FILES", that will open the Half-Life directory in a file manager. The standart path on Windows is "C:\Program Files\Steam\steamapps\common\Half-Life", on Linux it depends on your distribution, on my Arch Linux installation it is: ~/.local/share/Steam/steamapps/common/Half-Life/ .
It looks better on Linux than on Windows as the Linux libraries are taking advantage of SDL2.
The server library for Linux (dlls/spirit.so) is the original Spirit of Half-Life 1.2 code implemented into the hlsdk 2.3 (with a few changes in order to make it work...). The client (cl_dlls/client.so) is build from unchanged hlsdk-master code as I was unable to make the client library work properly with the spirit code (or more precisely - unwilling to sort through that undocumented trash).
Initially I wanted to release the Linux libs separately to be used in order to make any SoHL 1.2 based mod work on Linux. But since I did make some changes and I didn't build the client library with the spirit code at all, I'm not sure about how compatible the libs will be with other mods (though I think most Singleplayer mods based on spirit 1.2 should work fine with these libs). I did play through Blbej Den on Linux without an issue (though Blbej Den is only taking advantage of a few of the spirit features...)
Fell free to test the Linux libs with other SoHL 1.2 based mods (just modify their liblist.gam and copy over the dlls/spirit.so and cl_dlls/client.so), you can also reupload the libs separately wherever you want. I just didn't want to do it as I'm not sure about compatibility with other mods and I don't have the time to test it with them.