Slay the Spire

Gameplay

Slay the Spire is a roguelike deck-building game. At the start of a playthrough, the player selects one out of four characters. Each character starts with different health amounts, a unique starting relic with a special ability, gold, and a starter deck. Players will only obtain character-specific cards and relics throughout the run.

The goal is to work through several floors of the 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 which vary in strength; elite enemies which offer enhanced rewards; campfires to heal or upgrade cards; shopkeepers to buy cards, relics and potions from, as well as to remove cards from the deck; chests with random loot; and random choice-based encounters.

Combat is played in turns. Each turn the player receives a fresh hand of cards and three energy points. The player can play any combination of cards as long as they have the energy to pay for the energy cost of each card, and at the end of the turn, all cards not played are sent to a discard pile. Players' cards vary by character but generally consist of attack cards to damage opponents, skill cards that buff themselves, debuff opponents, or add to their blocking power for the turn, and power cards where the effect remains in play until the end of combat. Each opponent on the field will telegraph what move they will make: if they will attack and with how much damage, if they will block, cast a spell to buff themselves or debuff the player. In some cases, the opponents' attack or the player cards may add unplayable cards representing battle conditions like Wounds and Curses to the player's deck that can dilute a player's hand and may add negative effects while in the player's hand. The player can determine the best strategy to avoid taking any damage after they complete their turn. 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 relics that provide a permanent character buff for the duration of the game, such as increased maximum health, additional energy points, lower casting costs, and automatic blocking, 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.

Meta-progression

Slay the Spire features temporary deck-building and relic acquisition that resets upon victory or defeat, but also includes meta-progression across multiple play throughs.

Character unlocks

At the start of the game, only the Ironclad is available to play.

Silent: Unlocked after finishing a run with the Ironclad.

Defect: Unlocked after finishing a run with the Silent.

Watcher: Unlocked once the player has unlocked the Defect and won at least one run with any character.

In addition to unlocking characters, players earn XP based on their performance in each run for each character. Each has 5 levels that permanently add new cards and relics to that character's potential pools in subsequent runs.

Act IV and the true ending

After a player successfully completes a standard run (defeating the Act III boss) with the Ironclad, the Silent, and the Defect, special keys become available in future playthroughs:

Ruby Key: Obtained by choosing to recall at any Rest Site instead of resting or upgrading a card.

Sapphire Key: Obtained at Non-Boss Chests by taking the key in place of the chest's relic.

Emerald Key: Obtained by defeating an empowered "Super Elite" or "Flaming Elite" enemy marked on the Act map.

If a player collects all three keys in a single run and defeats the Act III boss, they unlock Act IV. This final chapter consists of a Rest Site, a shop, an Elite encounter against the Spire Shield and Spire Spear, and the game's ultimate boss, the Corrupt Heart.

Ascension mode

Defeating the Act III boss with a given character unlocks **Ascension mode** for that character. Ascension is an optional, 20-level difficulty system. Completing a run at the highest unlocked Ascension level unlocks the next tier sequentially for that character, with modifiers stacking cumulatively.

Development

Slay the Spire is developed by Seattle-based studio Mega Crit, with Anthony Giovannetti and Casey Yano as lead developers. Their initial goal was to fuse the concept of a roguelike game with deck-building games like Dominion. The game was also inspired partially by the Netrunner collectible card game, of which Giovannetti was a fan, and for which he maintains a community website. The game was built on the libGDX framework. It was originally chosen because its Java runtime allowed it to run on Windows, macOS, and Linux, but Yano later expressed frustration with it frequently being broken by operating system updates and its lack of console support.

To help test and get feedback on the game, Giovannetti turned to expert players in the Netrunner community. This was also necessary to determine appropriate balance for the cards they added, as balancing the difficulty of the game against the randomness of the roguelike encounters and the card-based play was difficult. By using a large number of playtesters, along with gameplay metric reporting from the game client, they were able to determine what cards had positive designs and which cards to remove. For example, they became aware of cards with too low a value for the game when they were not picked by players when offered, and found cards that were overpowered if they occurred too frequently within game-winning decks. They had no issue when players discovered card synergies that created powerful combinations, a factor of concern in typical collectible card games, as it was a single-player game and there would be no opponent that would feel overwhelmed by these combos.

Originally, enemies did not show their next intended action as is common to most turn-based role-playing video games, but this design did not mesh well with the roguelike nature of permadeath. During playtests, they found that players were confused about the number of card abilities without any clear situation to apply them. They first created a "Next Turn" system where the player could select individual targets to see what their chosen action would be in part of the game's user interface. The "Next Turn" system brought something unique to the game, according to Giovannetti, and enabled them to create new buffs and debuffs that were easy to describe to players through the interface. However, from a user-interface perspective, there were still issues particularly when multiple enemies were present. They then transitioned from the "Next Turn" to the new "Intents" system, which used icons to represent the enemy's next move, though originally this lacked exact numbers for attack values, instead representing certain ranges of attacks by different weapons. Giovannetti felt they didn't want to present too many numbers to players to overwhelm them and make the game off-putting, but they discovered through playtesters that having the numbers available was more engaging, did not require the player to have to memorize what each symbol meant, and enabled players to create new strategies. The approach for players to progress through the spires with branching pathways and random events was inspired by FTL: Faster Than Light.

Reception

According to Mega Crit, the game's first early access release in November 2017 was very slow, with about 2000 copies selling across the first weeks, the period in which most games sell the most copies. While they had seeded redemption keys with streamers and influencers, these had not converted into sales. It was not until a Chinese streamer featured the game on their channel that had over a million views that Mega Crit started to see a large rise in sales. During the week ending January 21, 2018, Slay the Spire was the second highest-sold game on Steam. By February 2018, the game had more than 500,000 players, according to SteamSpy estimates. Mega Crit announced that by the end of June, sales of Slay the Spire had exceeded 1 million, and reached 1.5 million by March 2019.

On release, the game received positive reviews, with a Metacritic aggregate rating of 89 out of 100. OpenCritic determined that 98% of critics recommended the game.

Awards

IGN named Slay the Spire as the Best Strategy Game of 2019, while PC Gamer gave it the Best Design for 2019. IGN later ranked it as one of the best 25 PC Games from the past decade, and one of the top 10 roguelike games.

Board game adaptation

Mega Crit announced in January 2021 that they were creating a cooperative board game adaptation of Slay the Spire with Contention Games. The game features more than 730 cards total, with four possible player characters to choose from. A notable difference from the video game is that the game can be played co-operatively with four players. A crowdfunding campaign for the board game was launched on November 2, 2022, and reached its funding goal after just 6 minutes. The campaign reached US$1.4 (equivalent to $1.5 in 2025) million in its first day, and finished after raising nearly US$4 (equivalent to $4.4 in 2025) million total. CBR included it on their list of most anticipated tabletop games of 2023.

A crowdfunding campaign for a reprint of the original board game, plus an expansion pack titled Downfall, was announced in September 2025. The expansion pack is based on a popular mod for the PC version of Slay the Spire likewise titled Downfall, which features the game's bosses as playable characters, defending the Spire from the heroes.

Sequel

Mega Crit announced in April 2024 that a sequel, Slay the Spire II, was planned to be released in early access in 2025. The game will see returning characters the Ironclad, the Silent, and the Defect, and at least two new characters, the Necrobinder and the Regent. The sequel also introduces cooperative play for up to four players. Mega Crit stated that they were inspired to make the sequel due to the amount of fan support they received for the first game, and plan to release the sequel into early access to work along with fans to finalize the game. As a result of the changes with the Unity engine licensing, Slay the Spire II is being developed in the Godot engine. Mega Crit delayed the release in September 2025, later confirming that early access would begin on March 5, 2026.