Being one of the original five worlds (the others being Icy Mountains, Dusty Desert, Cavernous Caves and the Crazy Asylum of Madness), it is part of the world selection globe in the original game and does not have to be accessed via selecting "Custom World". Beating it is a requirement to access the Crazy Asylum of Madness in the original game. In Supreme With Cheese, Spooky Forest! is one of the worlds selectable from the start, but is no different from other worlds in terms of significance.