In 2019, Diablo creators Erich Schaefer, Max Schaefer, and David Brevik told a story about Diablo 2's development, saying their entire backup of the game's source code and assets had been lost. As Gamespot quoted, it was "Irrevocably, fatally corrupted," according to Max Schaefer.
The Schaefers remember piecing the game back together from files developers had taken home and successfully finished the game, but with many of its development files missing. "We lost a lot of the assets, art assets," said Erich Schaefer. "It would make it very difficult for Blizzard to do a Diablo 2 remaster because all the assets we used are pretty much gone. They'd have to make them from scratch."
That's exactly what Blizzard did for Diablo 2: Resurrected, and according to Diablo lead Rod Fergusson and principal designer Rob Gallerani, the code and asset loss wasn't really as bad as the Schaefers remembered.
"I have to give props to Andre Abrahamian, an awesome designer at Blizzard working with us," said Gallerani, who works at Vicarious Visions, the Tony Hawk 1+2 developer that was recently turned into a full-time Blizzard support studio. "He went to people's desks just like, 'Hey, do you have anything left over?' Not only did we get the codebase, but we have a lot of the original assets. When you see the video of Tyrael's wings in HD, they actually are the original model from the original Tyrael's wings. I think that's one of the few assets that we just took verbatim."
Gallerani said that they had other assets pulled from all sorts of sources. For example: 3D models of the Lut Gholein market booths used for marketing stills. In the original Diablo 2 those were turned into 2D sprites, but Blizzard was able to recover the 3D files.
"Yes, data losses happen," Gallerani said. "I wasn't there exactly to know what exact things disappeared. But we still have the code. I mean, the game still gets patched, right, even after all these years."
Blizzard rounded up all of that material before it started work on Diablo 2: Resurrected, but the original art assets actually weren't vital because they remade "every single asset in the game," Fergusson said. Resurrected lets you switch between the classic graphics, which are untouched, and a completely new 3D engine. The cutscenes have been entirely remade as well.
"Because we have original people who worked on [the cinematics], we can have a lot of conversations around intention," Fergusson said. "We went in with, 'What would their intention be if they had the tools that we have today?'"
The code, more than the original art assets, was vital for Diablo 2: Resurrected, and that thankfully wasn't lost.
"When you dig into the code, there's Diablo 1 code in there. There's a lot to discover and a lot of intricacies," said Fergusson. "That's what makes it have its personality. The notion that the old code works the way that it does means you have the game that you have. If we were trying to change engines and recreate it and we didn't have those intricacies of the old code, it wouldn't feel the same. We're actually really grateful that we have what we have, because [players] can have that authentic experience."
- Read more about what's changing and what's staying the same in Diablo 2: Resurrected
- Good news: Diablo 2: Resurrected won't affect classic Diablo 2, unlike the launch mess with Warcraft 3: Reforged