No doubt this is a great moment for GOG, BUT...
...Diablo without Hellfire is just meh, I know, I played both versions in the past.

Unless...
"Blizzard and GOG.COM have collaborated on an updated version of the game, which includes out-of-the-box Windows 10 compatibility, and a host of bug fixes."
...that means this version has everything Hellfire had, like Monk class, run button, additional dungeons etc.?

Looking forward to see more Blizzard titles released here, of course.
Not so much for my own sake as I already own the ones I like the most and have played others and don't really need another playthrough when you have done everything in the first go.
All legendary games belong on GOG.com, so that counts a lot of Blizzard ones for sure.

good job GOG!

Hope Hellfire can be subsequently offered through GoG too.
Will get me 2 copies of the base game as soon as I get home though.

Did the hell froze over or is that that still waiting for the release of Command and Conquer?

Even SEGA? There's still some hell left to freeze over....

Wow, this blew me away. I never expected to see anything from blizzard here.

Thank you a lot ^^
Diablo 2 next?
Or Warcraft:Orcs & Humans.

SEGA didn't include Denuvo with Yakuza Kiwami and Catherine Classic, so that's a good sign that things are progressing slightly over there.

Isn't that what GOG stands for?

GOG's Twitter page already confirmed that Warcraft: Orcs & Humans and Warcraft II are in the works. No idea when, or whether Warcraft 2 will include Beyond the Dark Portal, but it's something to look forward to. :)

Damn, just playing a bit for a few minutes and then Dioblo get released here. BAM!
Great addition!

Edit:
Where is the addon Hellfire?

Should answer a few of the recurring questions (from the news post on the official Diablo site):

FAQ

Q: What languages will Diablo be localized in?
A: Diablo is available in English only.

Q: Where do I go for customer support related to Diablo?
A: For payment, purchase, download, installation, patching, and troubleshooting, please contact GOG directly. For technical support for logging into Battle.net, please contact Blizzard Support.

Q: Why are there two versions of the game?
A: Diablo is available in its original, unchanged Battle.net-compatible version as well as a GOG-enhanced version.

Q: What is different between the Battle.net and GOG-enhanced versions of the game?
A: The original Battle.net version of the game is completely unchanged and allows players to connect to one another through Blizzard’s Battle.net online-gaming service.

The GOG-enhanced version offers several quality of life additions, including minor audio fixes, up-scaling support for resolution and refresh rate control, and compatibility fixes. Please note that this version cannot connect to Battle.net and only supports multiplayer via LAN and P2P connection.

Q: Is the GOG GALAXY client required to play Diablo?
A: While the GOG GALAXY client offers streamlined features for managing installations, it is not required to play Diablo.

Q: What are the system requirements for running Diablo?
A: The full list of system requirements is available on GOG.COM.

Q: Will Diablo be available on the Blizzard Battle.net App?
A: No, Diablo will not be available for sale or download through the Battle.net App.

Q: Is Diablo: Hellfire supported/coming to GOG.COM?
A: We have no plans to bring Diablo: Hellfire to GOG.COM at this time.

Q: Is Diablo II coming to GOG.COM?
A: Diablo II and Diablo II: Lord of Destruction are currently available for purchase digitally on the Battle.net Shop. We have no additional announcements at this time.

Q: Are other classic Blizzard games coming to GOG.COM?
A: Yes! We have announced that we’re partnering with GOG.COM to release Warcraft: Orcs and Humans and Warcraft II. We’ll reveal more information at a later date.

Oh so this is how Bobby Kotick is gonna make up for the money they're going to lose after firing so much of their staff.

Also, fuck Activision and their refusal to lower the price in my region.

Oh wow, did not expect this one. I voted on it but I never thought it would actually happen! Fingers crossed for StarCraft and Diablo 2! Good work GOG and Blizz!