A wizard discovers a strange tome with tales of adventures in far off lands. When he sleeps that night, he finds himself transported to those lands and confronted with those adventures. But he need not face them alone, for faithful companions from far and wide are summoned in their dreams to stand by his side…
This was an actual D&D mini-series I ran. There was one central PC (the aforesaid wizard) and each time he was drawn into a dream adventure he could pick from among all his allies who would would join him no matter where they were in the waking world. Naturally that turned out to be characters who belonged to players who could make it to that game session — what magic! The title came from the chapters of the book (poetically called cantos), each of which was a different adventure.
By day the heroes were all back in their respective cities, dealing with their own affairs, including some unrelated solo adventures on their own turf. At night they go to sleep and magically come together to continue the dream adventure.
Clever little premise for a game, huh?
The thing is, there is no meat on dem bones. The “any PC anywhere can join you” was convenient, but as far as the dream quests went, much like a city floating in the clouds, it sounds fantastic but doesn’t actually change anything. The PCs still just go through the adventure like normal. It’s fancy window dressing with no real heart, a Not So Grand Experiment.
There are lots of “fantastic” elements you can include in a game that may seem amazing, astounding, trippy-freaky-cool, but wouldn’t really make any difference in how the players behaved or thought about the game. There may be a moment of “cool, galleons navigating the spacey void!” (possibly with talking hippo guys) or “cool, it’s like a normal city, but in a bubble beneath the sea!” but then the players go about their business and forget about the fantastic bit entirely. They have sword fights on the galleons (in space or not), they look for pawn shops in the city (underwater or not).
It’s not that you shouldn’t have wild, fantastic elements in your game that would make Lord Dunsany weep for joy — by all means, have at it. It’s that you shouldn’t expect a few wild, fantastic details to create a wild, fantastic game. You could even argue that the more fantastic the setting becomes, the easier it is to ignore it.
So just ask yourself: is this fantastic detail you’re adding the heart and soul of your game, or is it just a nice bit of flavor? If you can remember which it is and not expect it to do the heavy lifting for you, you’ll do fine. Because you can have a boring sword fight on top of a giant flying turtle as easily as you can on the ground.