Which is faster? How can I play the other one?

There is 2 secret levels in the game, taken from steam:
"Hold P on keyboard while loading Sugar Candy level to get secret level.
Hold U on keyboard while loading Arcadia to get secret level."

I've never timed the levels myself. If you decide to time them however, please let me know the results.

Thank you! I'll let you know!

Candy level is a lot faster, portal level requires you to get the cake and you need a lot of boxes for this. By the end you move so slowly.

Arcadia has a higher object requirement than its hidden counterpart so it's always faster to go to the box stage

In regards to sugar candy and the portal level, I've gotten fairly comparable times, though I think with optimization you could get the portal level to be faster because of jumping