In order to celebrate Diablo's 20 years anniversary i bring you Diablo HD mod by BrightLord. Besides the files you download you also need to copy the diabdat.mpq from any D1 original CD to game folder, wherever you keep it, plus have installed .NET Framework 3.5 and Microsoft Visual C++ 2010 Redistributable, these two you can get from MS website. Also note that this does not include any Hellfire (expansion) content.
http://s000.tinyupload.com/index.php?file_id=38986610238880893758
And bare in mind that it's still in alpha and since D1 community is so small it's public. Last update was released yesterday and you can read changes here http://awake.diablo1.eu.org/mod-release-0-1-0-test-t1643.html and sometime in 2017 there will be more work work on it.
Also i had done docs for Belzebub build last year and most info is still the same, items are the same, there are some changes to crafting recipes but just in the amount of required materials, Butcher quest has changed, some more shrines have been added, some character skills have been reordered and you can read more about it in the changelog, i have't played it all yet so i dunno everything myself. You can get docs from http://www.mediafire.com/file/0ke321s14k4pbie/docsV3.zip
Have fun and enjoy!