Fallout 3 launched in 2008 as a 3D open-world game, and it has since spawned two similar sprawling RPGs in Fallout: New Vegas and Fallout 4. These have proved incredibly popular, but the series could have been very different if two canceled Fallout 3 projects had seen the light of day.
Feargus Urquhart, CEO of Fallout: New Vegas developer Obsidian Entertainment, told IGN that the company worked on multiple Fallout 3 projects in its previous guise as Black Isle Studios. Urquhart recalls one project that went on to become Icewind Dale.
"Now 3D was the cool stuff. So we were going to move from being a 2D engine and be a 3D engine, and so we actually started working with this 3D technology called NDL," he said.
"What happened was, we were moving forward but we were really learning, and it was where Interplay [publisher of Fallout at the time] started to run into financial trouble--and that was where Icewind Dale came from."
"The Fallout 3 team became the Icewind Dale team," Urquhart said. He went on to say the company wanted to make Icewind Dale as a dungeon-crawling "counterpoint" to Baldur's Gate's more story-driven elements.
This wasn't the only Fallout 3 project, however. The CEO said another version, codenamed Van Buren, "was the second Fallout 3," after the first one became Icewind Dale. Van Buren has been more widely reported, and you can see more of it on YouTube.
Eventually, Black Isle studios--which developed both the original Fallout and Fallout 2--was shut down by Interplay, and Bethesda took over the Fallout franchise. Many of Black Isle's staff went on to work for Obsidian, which has since developed Fallout: New Vegas.