Would the first one be this
? Because I remember talking with you about starting up a game of it here, before I run into issues. This thing here is much more freeform.
As for the second, just cut out the sentences that contain a reference (Shattered World is a trope btw, not a work), and it's pretty much the same description. But here's an elaboration anyway.
The old world (nondescript, could be just about any setting) is brought to a violent end by a mysterious cataclysm which leaves behind only a bunch of floating islands covered in weird crystals (check the World In The Sky
trope, that's pretty much what I'm going for). Some of these have people still on them, but the majority of the world's population just fell into the newly opened abyss. To make matters worse, all of the survivors get mysteriously ill; some of them suddenly recover to find themselves slightly stronger than before and acquiring magic (something that this world has no prior experience with). Those who don't make a recovery within a month or two end up dead.
Anyway, the game would start a while after that, once they've gotten to grips with the magic system (those crystals can apparently amplify their powers, in different ways depending on the type of crystal involved), when one guy on a particularly huge island uses the particularly huge crystal at it's heart to call out to anyone else out there. The PC's travel there by various means and begin building a settlement there using whatever they can scavenge from the other islands, whether supplies, building materials or big chunks of crystal (every island has a crystal at it's heart that allows it to float). But of course, there are complications with that. Monsters, which might be mutant animals or just popped up from the same place as the cataclysm, prowl the islands looking for things to eat, and apparently you're very tasty. The village, eventually a fortress town, eventually a citadel etc., has to keep fending off attack by particularly desperate, stupid, or quite possibly vengeful monsters. Not to mention that other groups of survivors might be building cities of their own somewhere out there.
So, yeah, basically.