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.[5] 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.[4]