I was watching a youtuber's playthrough of Dark Souls last night, and I found myself wondering if it was Open World or Linear.
While watching the poor guy die repeatedly to a Big Demon Thing because he'd forgotten how to drink potions, I began to formulate in my head how to make a truly open-world RPG. Hereafter follows my theory on how to make a truly open-world RPG.
My Theory On How To Make A Truly Open-World RPG
First, let's start with the name.
List A: "Rift", "Void", "Realm", "Shard".
List B: "Jumpers", "Walkers", "Leapers", "Runners".
Combine the words from A with the words from B until you get a combination that has not already been trademarked by a gaming or fantasy company. There's your name and plot sorted.
The Universe of this game is a shattered place of different realms, connected by portals. Only a very few people are born with the ability to traverse the void between realms. ("Very few", in this case, of course translates to "everyone who buys the game".)
After the character creation process (where they have the usual RPG classes and abilities to choose from) and a basic tutorial where the player leaves their home town, learns how to cast spells or hit things with swords, they discover their very first portal and step inside.
The player then finds themselves on their own personal VoidWorld (name pending). It's a rock floating in space. There's the portal they came through standing on the rock like a full-length mirror. There are two stone obelisks, one black and one red, a stone coffer for the storagement of loot, and a small pool of glowy water that heals and restores anyone who steps into it. They can't fall off the rock. Attempting to jump off results in them just running around the side, like Le Petit Prince on asteroid B-612. This is a safe spot, their respawn area and a sort of in-game "lobby".
If they break the mirror they came through, the pieces fall to the ground, stay there a moment, then spring back into the frame. This process conceals the most important mechanic in the game.
The Most Important Mechanic In The Game.
Once they break the mirror back to their home-world, they break the link connecting their VoidWorld to their home. When the mirror re-forms itself, it generates a new connection to a brand new unexplored world.
In reality, what they have done is simply deleted the save-file containing their home world, and instructed the game to generate a brand new world file. Stepping through the new portal, they find themselves in a randomly and progressively generated world - like Minecraft - that extends a theoretical infinite distance in all four directions. The graphics would be slightly less chunky than Minecraft, though. It should be entirely possible to progressively generate worlds with the graphical quality of a (pre-Skyrim) Elder Scrolls game.
It's only a theoretical infinity because, while the mobs and creatures around the portal are mostly harmless, their power is directly related to the X/Y co-ordinates they spawn at. The further the player explores away from their portal, the more powerful and dangerous the enemies they encounter will become, but the loot they find will increase in quality accordingly. And like Minecraft, there would be structures to explore (Caves, Mine-shafts, Fortresses, Towns and Villages, but also Ruins and Labyrinths and Dungeons and whatever else can be progressively created). Some worlds may have towns populated by NPCs with quests to offer and trades to... trade. Some will have towns full of hostile NPCs who need to be conquered or pilfered from. Some worlds will be barren deserts. Some will be lush forests or arctic tundra. Some will be intricate cave systems with no surface to visit. Some will be floating islands connected by bridges, with nothing below but fall-y doom.
But each world is persistant and has enemies don't respawn when they're killed. Once a player has reaped the benefits of a world, but can get no further due to the enemies getting too strong, he returns to his VoidWorld, shatters the mirror, and then steps through to discover a brand new realm to explore. Perhaps in his or her travels, they will be lucky and discover a Void Mirror. If they manage to get that home, they can create a second portal in their VoidWorld. And with a second (or third or fourth) portal, they can afford to leave one permanently connected to a specific world. Now our plucky adventurer can clear a castle of its evil denizens, take it over, and make it their base of operations.
But Wait! There's More!
"This is all very well, peon47," you say, "but every game has multiplayer now, and dungeon crawlers are only fun if you can bring along a friend to act as bait for the skellingtons." Well, reader, I am glad you brought that up. Now we come to the purpose of the two obelisks found on every VoidWorld.
The player invites a friend to their group, and a portal to the friend's location appears on the side of the obelisk. It's that simple. If there's five people in the party, the player gets portals on all four sides of it to choose from. Jumping into one of them ports them straight to their buddy.
The Red Obelisks function similarly, but for PvP purposes. If someone issues a player a challenge, the player (and his or her friends) can travel directly to them through a red portal.
It was at this point that the guy in the youtube video finally killed the Big Demon Thing.