A big part about Sandbox play is the "Game About Nothing" (like the TV show Seinfeld). An Open Sandbox lets the players have their characters do nearly anything they wish on a whim. And quite often this is non-combat, non-adventure Slice of Life stuff. The character's might go shopping or attend a play or such things. This is common in open type online video games
I guess you can say loose connections....but it is still like episodic TV...where other shows/adventures really don't matter.
Well, not escaping.....
You can see people on online games, where they might even pay, but they don't really play the game much. They don't care about the Quests, and Levels and all that. They just want to socialize and hang out. Or they pick some minor part of the game they find fun....maybe like growing corn...and they become a corn farmer.
And activities like Second Life, where you can make a house or whatever and just show it off.
Yes. In Pure Sandbox Play the goal is simply to play. Or use up time.
Yes, as it is about how you play out the game.
Woah....so a more typical Sandbox does not have that much detail. Maybe the dm-player makes a map, but they sure are not making points of interest. Once the DM starts to create more then a small amount, the game slides down the slipper slope to being a Linear Game.
A more Sandbox game simply has a 'unknown cave' marked on it. And a player or two then say, and alter game reality, "there is a powerful magic sword in that cave we want", and the DM-player bows quickly to say "yes players". And because the players said the sword was in the cave, it is okay for the game to be linear about that single player approved bit of data. So the characters have to travel to the cave to get the sword.
If the players approve of a small part of the game world being Linear, then it is okay for the dm-player to make a linear encounter around that single player approved item.
But the players still have the majority control over the whole game world and what and how and why and when they want to do nearly anything.
you are missing the structure part.
Anything except a True Sandbox game that is pure chaos, needs to have at least a slight Linear Framework. Otherwise it is pure chaos. A goal in linear, but that does not effect the game play.
Take two groups, they both say "we will save the princess".
In the Linear Game the DM preps for the game, often tons of maps and text and work and effort..even to the point of writing an adventure. And the DM locks in all the details. Before the game starts the DM can tell you the what, why, how, where of the whole 'save the princess ' idea. Who did it, why, how, where she is and all sorts of details. It is all set by the DM....the players have no say. During the game the players must follow the DMs path to find the princess and save her, based on all the details.
The sandbox game....all the details are left open. Often the DM-player provides no details...but may provide a light dusting of vague details. Everything about the whole idea is to be set by the actions of the player characters. Whatever the players choose to do under the idea 'save the princess' becomes the game reality of saving the princess. The DM-player her has little or no power and simply makes what the players tell them to make and have the PCs save the princess.