Tim Schafer wanted to "compete" with classic D&D CRPGs like Icewind Dale by cranking up the fantasy in Brutal Legend: "Let's really exaggerate it"

gamesradar.com:

Brutal Legend is one of the oddest big budget games maybe ever because it's such a wild mish-mash of ideas. It's an open-world action game. It's a top-down RTS. It's a classic Double Fine comedy. It's a heavy metal dreamscape. But part of that DNA actually came from classic CRPGs, which the studio wanted to crank up to absurd levels.

To celebrate 15 years since Brutal Legend's original release, developer Double Fine recently published a retrospective blog about the game's conception, development, and, err, legacy, delving into everything from its genre mash-up to Jack Black's eventual involvement. But one interesting tidbit comes from Brutal Legend's unexpected connection to old-school high fantasy RPGs like Icewind Dale and Neverwinter Nights. 

Director and studio founder Tim Schafer shared that he first imagined a version of Brutal Legend's swords and magic fantasy after he listened to Black Sabbath's Iron Man. "You fantasize when you listen to music," he said. "I would imagine all kinds of different scenes when I was listening to songs." Turns out, classic fantasy was in vogue at the time with games like Icewind Dale, which often shared a large audience with the beloved adventure games that Schafer cranked out while working at LucasArts (RIP) in the '90s, namely with stuff like Grim Fandango. 

Essentially, Brutal Legend's twisted world was the middle point between those more traditional fantasy games and the imagined heavy metal iconography that would play in Schafer's mind when listening to Ozzy Osbourne. Finding inspiration in unexpected places - or by banging two unexpected things together - isn't too unusual for the studio, though. Later in the blog, when talking about mixing RTS elements with action bits, Schafer said he'd often have ideas that "won't go anywhere in my brain for years... then two ideas will crash into each other and now that's a thing."

“People ask about Brutal Legend all time”: Tim Schafer says he’d rather expand on the 15-year-old game’s