I found three of the real owls needed to get the anticube and open the secret door in the graveyard world. Throughout the game, there are four owls perched on trees in the levels. if you go up and press B next to them, they will fly away and you'll be able to see them at the owl statue that follows you in the graveyard. Get all four to get an anitcube and unlock the secret door there. There is one in the tall tree with bouncing mushrooms, one in the first warp zone hub, and one near the windmill. Anybody know where the last one is?

Go back to the starting village, there is a hint to all of the owls' locations.

@Aishan: which house in the village?

The one where the eyepatch fella hangs out.

@Aishan: Thanks!! really helped a lot. Do you happen to know how to get the chest that is too far to jump across to get in one of the first areas. The one where the treasure map shows a red block that is invisible? And the chest in the cave area that you have to look up to see. How do I get to it?

@ingloriousthomas: For the invisible block, you just have to orient the world so it matches the maps orientation. Then, you jump on the block, then rotate the world so you can reach the chest by jumping.