Slay the Spire is a combination of roguelike-like gameplay with a deck-building card game. At the start of a playthrough the player selects one of three predetermined characters, which sets a starting amount of health, gold, and an initial deck of cards with basic attack and defense cards. The goal is to work through several levels of a spire, each level having a number of potential encounters distributed in a branching structure with a boss character at the end of the level. Encounters include monsters, campfires to heal or upgrade cards to more powerful versions, shopkeepers to buy cards and potions as well as to remove cards from the deck, chests with random loot, and random choice-based encounters.
If the player's health drops to zero, the game is over and they must restart from the bottom of the spire. Otherwise, if the player defeats all the monsters in an encounter, they typically receive gold and a choice of one of three randomly-selected cards to add to their deck, if desired. Other loot that can be obtained from monsters or other encounters include trinkets that provide a permanent character buff for the duration of the game, and single-use potions that can be used during any turn for no cost to restore health, buff the player, and debuff or damage the enemy.
