First and foremost, After The Cataclysm is built to be a loveletter to old 16 bit era RPGs. 

Plot: The world you inhabit has been ravaged by the Cataclysm, an  event created by a previous group of heroes when they destoyed the ancient artifact that granted the Emperor his power. You are one of the many people picking up the pieces in a reality broken both forwards and backwards. No one can quite agree when the Cataclysm happened or how it happened, only that it ravaged the world.  The specifics are less important than survival. You are a Wild Wanderer, part messenger, part adventurer, and you are picking up the broken pieces. 

Design Principles:

1- The game, while an homage to SNES RPGs at large, should not be so reminiscent of any one inspiration that it feels like it trying to "be" them. I am not trying to remind people of other more classic games they could be playing. 

2 - The game takes a more granular approach similar to TTRPGs . Characters should have interactions and choices outside of combat that leverage their classes and backgrounds. Players should be able to  sneak through dungeons or persuade their way through certain roadblocks, and the system (specifically experience and levelling) should respect these systems and reward progress, but not so much that it creates an optimal party build

3 - The game has randomly determined elements, but takes a guiding hand to ensure that designs for things like towns and dungeons are still coherent. This requires a moderate level of simulation on the back end. 

4- There are six different potential big bads and six potential story avenues. Three of each will be available on launch with more coming out in a periodic fashion

5- Each play through should be roughly 15 hours to complete, with the intent that you will play through multiple times to experience many different stories.

6- Play through should have some level of reference to previous play throughs, whether it's through the odd recurring character or visiting your old town with a new character. 

7- Combat needs to be engaging enough to play through multiple times and not be bored by a single element. The intent is to create something that is slightly more "TRPG" for the time with movement without making it an utter slog.

8 - The intent is to modify strange design choices of the past (including some that may have had strange marketing origins) without fundamentally undercutting the formula of what makes a SNES RPG, i.e. Monsters in dungeon will be represented on the map (to be snuck past), but there are random encounters in the overworld. However, the intent is to make random encounters very rare (You might expect one encounter moving from town to town)

9- You are not supposed to see all of the content in one run. There will be some elements of timing (quest expiry) and consequence (periodic saving after hard choices). The intent is that the choices you make should add INTERESTING content rather than things that are objectively better or worse.  Your protagonist may be silent, but it doesn't mean they are formless. 

----

There's a lot more, but this is the introduction.  Like many projects it is very ambitious and is a very long way from completion, but the goal is to have a SNES style RPG that grants so much real variety that it is still surprising you on the 10th playthrough.