Elden Ring has become one of the most mysterious games currently in development. However, one of the few details actually known about this title is that it's going to be what FromSoftware calls an 'open-field' game. Not open-world, but open-field.
There's a subtle difference between these two concepts. There have been a ton of open-world games, ranging from Skyrim, to Valheim, to Grand Theft Auto, to The Witcher. These games offer nearly unlimited freedom to the player in terms of where to go, while an open-field doesn't necessarily quite do this.
Skyrim's Open World
Skyrim's open world is honestly a little staggering, and it's easy to take it for granted now that the game's been out for so long. But there's so much freedom in Skyrim; right from the get-go, players can head to Riverwood and eventually Whiterun if they wish to follow the main quest for a little bit, but they don't actually have to do that. Players can simply... wander. Find something cool on the map, and head in that direction.
It's almost a guarantee that they're going to stumble across some kind of an interesting story, regardless of where they go. And even if they go through an entire cave or building and there isn't necessarily a story spelled out for them there, there's usually enough environmental cues and snippets of dialogue from those inside that the players can glean enough information to understand most of what's going on.
The point is, Skyrim is the epitome of an open-world game. Players can go absolutely anywhere they want, whenever they want, and the game is going to balance the characters accordingly, ensuring the player rarely gets into an area full of enemies they can't deal with.
Dark Souls' Open World
Dark Souls' world is a bit trickier to define. It's not quite an open-world game, though it is a game about exploring the world the game takes place in. It's just a bit more linear; players can't go anywhere they want right off the bat, at least not without progressing through the game to do so.
The Dark Souls world is narrower, more constricted into passages and alleyways than it is an open area where the player can go whatever direction they want. It's a good thing, too; the enemies in Dark Souls games aren't designed to scale with the power level of the player, the player is meant to become more powerful and/or skilled to match the enemies. If it were a game where the player could go anywhere they wanted right off the bat, it would probably lead to quite a lot of dying, more than is already typical in Dark Souls.
Elden Ring's Open-Field Design
Elden Ring's open-field design is probably going to be something in the middle of these two concepts. It's not going to be this open, sprawling world like Skyrim where the player can pick a direction and go. But it's also not going to be this constricted, narrow world made up of lanes like Dark Souls is. There will likely be some open areas where the player can poke around and see what they find, but these areas are probably still going to be fairly guided. It'll pull the player along to the areas that they're meant to go to, while still giving the player some authority to go see what they want to see inside that area.
With Elden Ring being a FromSoftware game, and a collaboration with George R.R. Martin, the world is probably still going to be chock-full of interesting lore and environmental storytelling, which is the biggest draw of the Dark Souls worlds anyways. So despite the difference in its construction, fans of Dark Souls are probably still going to feel right at home with FromSoftware's biggest title yet.
Elden Ring is currently in development.