Hey Guys ! I discovered that you can kickflip out of the extralevel ceilings. I got on top of the map in every chapter possible (cube in extra level) and realized that you can get the cube with you. Sad thing is that it seems you can only get back into the map at gates from mechanical doors, which arent existent in important levels. So yea, we can get out of bounds with a cube but we cant get back in the map usefully...
This is seen from ooB at chapter 3 sector 26..
EDIT: seems useless so yea, lets try to find something usefull above the map
Chapter 7 sector 66 ..... Kickflip to the left could land you ontop of the last level from where you could try to hit the loading zone for the epilogue.. Currently trying to land there
This would skip 5 levels + maybe you can bug into the epilogue !!!