Final Fantasy 6: Return to Darkness

Also... will there be more "extra" stuff added into the mod? Like a new dungeon, a casino or something?

There's somewhat of a final boss in the demo version, though it's still just the story boss of the area the demo ends at. Still, with the higher stats and HP values, he does take a bit longer to finish off.

As for extras, there are new items, and there will be a few extra bosses to fight. A new dungeon is also in thoughts, but I haven't gone that far into the plannings yet.8]