If you have 5 or more coin stars, look in the direction of the door (It is a sign, but, whatever). It asks you if you want to spend 5 coin stars on passing - don't worry, when you have paid, the road is always open.1. How do you get into the green mushroom house where the road does not extend into and which is blocked by a coin door in World 1
EDIT: God, why does the enemies dance to the music?? It annoys me like hell