When Blizzard first envisioned "The War Within," the next expansion for World of Warcraft that literally takes players inside the planet Azeroth, there was one major concern.

"Concerns about claustrophobia were a major aspect of this expansion from the very early planning stages," said game director Ion Hazzikostas in a recent group interview with PC Gamer.

It wasn't just the tight interior spaces that worried the developers: it was the darkness. Players have never responded well to relentlessly monochromatic, dark, or grim zones. For example, Mau, a hellish zone in the afterlife-themed Shadowland expansion, was heavily criticized by players because it met all three of these criteria.

So the developers decided that the underground zone of Azeroth should not feel that way.

"The theme of going underground can be quite dark. So how do we navigate that sense of oppression?" asked Gabriel Gonzalez, lead visual development artist, in a group interview I participated in. Gonzalez replied, "What we did was to really lean into the many story elements that would help us find ways to bring interesting lighting, beautiful landscapes, and interesting atmospheric effects.

The end result was a zone that didn't feel like it was underground, even though it was.

"It's very different from what one would normally expect from a cave environment," Gonzalez said.

Hallofall, for example. This zone is completely underground, but is illuminated by a huge glowing crystal on the ceiling of the cave, like a star far off the floor.

"It is vast. There is a ceiling, but it is far out of sight most of the time," says Hadjikostas. 'There's not much to block your view. It's a space that was created from the beginning so that when you walk on the ground, you don't feel like you're underground. You have to tell yourself that."

Ultimately, Gonzalez says, it should contribute to more challenging gameplay.

"Players tend to prefer zones that are a little more natural and where the lighting feels a little more comfortable," he says.