As of now there is nothing after the main story is done , on your map near where you fall thru does it look like a big green square under ground
##Spoiler maybe
hasty furnace
No i going to find the ((??)), and go througt the water North /east and suddently i going throug the ground and fallige beside a wortex, and end up in base again
hasty furnace
But falling thru the world is a bug
So when i upgrade the base all up - its over ?
cloud acorn
That's a bug I would make a report just in case it hasn't been reported yet , and ish