Kingdom Hearts/Halloween Town
Halloween Town is a world based on Tim Burton's classic stop-motion film The Nightmare Before Christmas. Similar to Atlantica, Sora's, Donald's, and Goofy's appearances change based on the environment - Sora becomes a vampire, Donald becomes a mummy, and Goofy becomes Frankenstein's Creature.
 Making a Heart
From where you begin, go forward to Guillotine Square. Pass the Heartless positioned in front of you and jump up a level. Go around to your right for a cutscene, where you'll be able to see Jack Skellington, who says he's going to talk to the doctor. Keep going to come across a door marked Lab Entryway. Go up the stairs to enter the Research Lab. After a cutscene, you'll see that Jack Skellington wants to make a heart for the Heartless so he can make them dance. Sora, seeing no harm in this, decides to help. After the heart fails, the doctor suggests finding Sally, who has memory. After the cutscene, you will get your next mission (find Sally) and also a new optional party member, Jack himself.
You can now leave the Lab and go back to Guillotine Square to begin your next mission, but not before you're stopped by the Mayor for a cutscene.
 Necessary Ingredients
Predictably enough, the Heartless have gotten out of control. Instead of ignoring them, you'll now have to fight them. Your next destination will be up a set of stairs leading to a gate. The gate should be labeled Graveyard. Here, after taking care of the Heartless, you'll find both Zero (Jack's loyal pet ghost-dog) and Sally, the person you were in search of. After this cutscene, you'll get what you needed (Forget-Me-Not). Now go back to the lab and talk to the doctor. After taking Forget-Me-Not, he'll tell you that one more ingredient is needed - Surprise - and that the Mayor should know where it is. Now leave the lab and go back to the Graveyard. Jump on top of the coffin at the end of the Graveyard and Examine ( and ). This will take you to a new location, where you'll find the Mayor. Now will be a small mini-game-esque sequence in which you'll have to Examine the tombstones in the order the ghosts appear. Now he'll tell you to look at the pumpkin, which is a large orange platform across from him. Atop it will be a treasure chest. Open it to obtain Jack-in-the-Box. Now go back to the coffin you came from (it's hiding behind the pumpkin) and Examine it to go back to the Graveyard you were in before. Go back to the Research Lab and talk to the doctor once again. A cutscene will follow where Lock, Shock, and Barrel steal the heart for their boss, Oogie Boogie. Your next task will be to get it back.
 The Stolen Heart
Leave the Lab to return to Guillotine Square for a cutscene. Jack summons Zero to lead the party to the culprits. He'll lead you back to the Graveyard. Here, a cutscene will be shown featuring Lock, Shock, and Barrel getting away by crossing Moonlight Hill, an iconic location from the movie. Once again, go to the coffin in the back and Examine it to end up in the same location as before. Examine the statue to open a new passage to a new location. Examine the hill for a scene in which the party walks across it. Simply cross the stone bridge here to be taken to Oogie's Manor.
The bridge that leads to Oogie's Manor seems to be worn and torn apart. Be careful not to fall off, because there's a climb up. This applies for the rest of the Manor - the farther you get through the mansion, the higher the climb will be. Fight the Heartless in front of the door to gain the option to Examine it. Lock on to the elevator in the room with and shoot Fire at it to get it to start moving. Take a ride on the elevator to get to a higher level. Follow the path of the bridge upward and then jump up the stairs. Here will be a large stone circular platform. Go to the right of it, follow the path and climb up the next set of stairs. At the end of this bridge will be the Evil Playroom.
After the battle, leave the Playroom and proceed to the final boss battle: the battle with Oogie Boogie.
 Oogie Boogie
From the bottom of the mansion jump to the platform on the left.(if you're looking at the doorway). Examine the doorway on the platform it will take you down to a new level to reach a green door with Oogie's face on it. This is the entrance to the Torture Chamber. A cutscene will show Jack demanding Oogie give the heart back, and Oogie swallows it, thus gaining full control of the Heartless.
After the battle, Oogie Boogie seems to be dead - only for the party to rush outside and find that Oogie Boogie has become his mansion, and that he has been overtaken by darkness.
After the battle, Sora will lock the world and, after another short cutscene, you'll be free to leave Halloween Town and move on to the next world.