The End is Nigh Guide
The Split is a bit of an unconventional world as it mainly serves as a crossroads between 4 worlds. The 4 worlds accessible from The Split are:
Overflow – Left
The Hollows – Down
Retrograde – Right via ledge smash
The Wall of Sorrow – Up
*You can also access the Overflow Cartridge by jumping up to going left where the large red arrow is.
Whichever way you choose to go, click the links above to reach that section of the level guide.