Upon reaching the dream world, this is the order you should get collectibles to optimize speed. 1: Tall Geta 2: Chromakey Dreamcoat 3: Phantom 4: Rusty Key 5: Tentacles 6: Halo 7: Karakasa 8: Light 9: Monochrome 10: Shovel 11: Koraiyn 12: Food 13: Guitar

Upon collecting all of these you will presented with the "Her" cutscene, signifying that you have beaten the game.