Screenshot of the level
1st ??? area
2nd ??? area Left path
3rd ??? area Left path
4th ??? area Left path
5th ??? area Left path
2nd ??? area Right path
3rd ??? area Right path
The Machine 4 is one of the Levels in The End is Nigh. It is connected to The Machine 3 from the bottom and The Machine 5 from the right, and "???" areas from the top. 5th ??? area (Left pass) is connected to Retrograde 15.
Collectables
Grabbing the ledge at the top right will make it come down, going up will lead to 2 Mega tumors.