The original Diablo is now available to buy DRM free on GOG.com. It’s not often a Blizzard game goes DRM free. The game is €9.99. More information can be found on a blog post on battle.net.
Diablo has been lovingly preserved in its original form, featuring HD resolution support and compatibility fixes brought to you by the GOG team to ensure compatibility with modern PC operating systems. Play on your own or with friends via network or direct IP. Explore randomly generated rooms, corridors, traps, treasures, monsters, and stairways, all rendered in their original three-dimensional, SVGA enhanced graphics.