One thing I am contemplating right now is a small, contained sandbox for a short campaign/long adventure. By some definitions, that isn't a sandbox because it is bounded both in space and time, but I think the definition still works at least well enough not to have to create a whole new term for it. In the precise example I am talking about I am thinking a barony suffering under the depredations of a dragon and the party comes in at the behest of the Baroness to kill it (the reward being the hoard). Everything else is up to them. they could conceivably just roll up on its lair but that would likely end in a TPK, so they can explore the area, talk to the people, delve the dungeons, etc... in hopes of finding tools that will help them kill it and take its stuff.
For those that care about strict definitions: is that still a sandbox? And does going in with a goal in mind count as a "railroad"?
For those that care about strict definitions: is that still a sandbox? And does going in with a goal in mind count as a "railroad"?