Bastion is an action/role-playing game set in a city called Caelondia after it has been destroyed by a disaster called "Calamity". The game follows a silent protagonist known as "The Kid" who tries to create a safe haven with the help of Rucks, who narrates the game. The kid must defeat the game's many foes with melee and ranged weapons and special skills. The Bastion, which acts as headquarters, can be upgraded with useful buildings.
As the Kid travels through the world, he will discover new weapons, upgrade materials, mementos and fragments. Mementos can be discussed with other characters in the Bastion and may reveal more about the world. The Kid can only hold two weapons and one special skill at a time, which requires switching them with others, considering player preferences and enemy weaknesses. Fragments are the game's main currency and can be collected by destroying objects, defeating enemies, or finding them.
The Bastion encloses six buildings that the Kid can restore and utilize. In the Distillery, the player can assign spirits to slots, providing passive bonuses during gameplay. At the beginning, only one slot is available; more are unlocked as the Kid levels up. The Arsenal stores all gathered weapons; players can switch between them. The Forge enhances and upgrades weapons using upgrade materials found in the world.
The Memorial offers challenges that reward additional fragments if completed. Lost-and-Found allows players to spend fragments to restore upgrade materials and unlock idols and spirits. Increasing game difficulty can be done by invoking gods in the Shrine.
One notable feature of the game is its dynamic narration, where narrating is based on player actions. For example, when the kid falls from a height, the narrator comments on the incident.
