In Vegetable Valley, above the room where you fight the tree boss, there is a door with a Star above it (it is circled in yellow in the picture below). For me, this room is all boarded up. How do I get inside?
2 Answers
This is a Warp Room. Unlike, say, Return to Dreamland, there isn't a world map that you can just access each level. Instead, the boss door is a doorway that leads to the next level, once you beat the boss. Travelling is done by simply walking.
The Warp Room is a method for accessing different levels without needing to walk across each of the intervening levels. Each one you unlock adds a new warp star in it that you can use to access a different level. They're always unlocked next to the boss door.
Until you have at least two Warp Rooms, however, you don't have a destination! So it'll be boarded up until you can actually use it, which is when you unlock the second Warp Room.
That's just the door to a warp star that could take you directly to a different world that you have defeated the boss. It is only opened after you have defeated at least two worlds (in other words, reached the third world). You could take that instead of using the other doors that takes you only to the next or previous world.
