Throughout your journey, you'll discover various collectibles that deepen the lore of Bastion and its world. These include Mementos, which are small objects that trigger Rucks' narration about past events or characters, and hidden areas that reveal more about the Calamity.
While not strictly necessary for completing the game, finding all Mementos provides a richer understanding of the story and its characters. Many are hidden off the main path, requiring careful exploration. Some Mementos are also tied to specific character interactions at the Bastion. Keep an eye out for glowing objects or unusual environmental details that might indicate a hidden collectible.