Bastion is an action role-playing game developed by indie developer Supergiant Games. In the game, the player controls "the Kid" as he moves through floating, fantasy-themed environments and fights enemies of various types. It features a dynamic voiceover from a narrator, and is presented as a two-dimensional game with an isometric camera and a hand-painted, colorful art style. Bastion's story follows the Kid as he collects special shards of rock to power a structure, the Bastion, in the wake of an apocalyptic Calamity.
Bastion is an action role-playing game with a level structure. The player character, "the Kid", moves through floating, fantasy-themed environments that form paths as the player approaches the edge. Levels consist of a single plane, and are viewed isometrically. They are filled with enemies of various types, which attempt to harm the Kid. The Kid carries two weapons, which may be selected from the choices available to the player at specific locations called arsenals. The Kid also has the ability to perform a special attack. Weapons and special attacks must be acquired before they can be used. There are a limited number of special attacks that the player can perform at any time, represented by "black tonics" that can be found in the levels or dropped from enemies. Special attacks may be used a total of three times. This maximum number of uses can be increased in the Distillery. The Kid's health is represented by a health bar, which can be replenished with "health tonics". Like black tonics, the Kid can only carry a certain number of health tonics at a time, and can replenish them by finding more in the levels.
Levels contain many different environment types, including cities, forests, and bogs. At the end of most levels, the player collects an item called a core or a shard; occasionally, the level begins to disintegrate once the Kid takes the item, forcing him to hastily retreat. As the player progresses through the levels, a voice narrates their actions. This narration gives scripted plot information as well as dynamic comments, such as on the player's skill with a weapon or performance while fighting enemies.
Between levels, the Kid visits the Bastion, where the player can use fragments—the game's form of currency—that they have accrued to buy materials and upgrade weapons. With each core the player collects, they can add one of six structures to the Bastion, such as a shrine, an armory, or a distillery, and each shard allows the player to expand a structure. Each structure serves a different purpose; for example, the distillery lets the player select upgrades, and the shrine allows the player to choose idols of the gods to invoke, causing the enemies to become stronger and giving the player increased experience points and currency. Experience points are used to determine the Kid's ability level; higher values give the player more health and increase the number of upgrades they can select.
Whenever the player leaves the Bastion, they can choose between one or two regular levels to play. In addition to these levels, however, the Kid can engage in challenge courses designed to test the player's skills with the weapons the player has found. They are called Proving Grounds. The challenges differ depending on the weapon, such as destroying a certain number of objects within a given time or breaking targets in the fewest shots possible. According to the player's score, different tiers of prizes are awarded. Additionally, the Kid can fight waves of enemies while the narrator tells a character's backstory by journeying to "Who Knows Where" from the Bastion. The back story battles occur during 'Memories.' The player earns fragments and experience for each completed wave. After the game is completed, the player can choose to begin a "new game+" mode, where the player replays through the game while keeping the experience points, fragments, and weapons that they have gained. This mode also offers more options in the buildings, as well as two more journeys to "Who Knows Where".