Slay the Spire II is a roguelike deck-building game developed and published by Mega Crit as a sequel to their 2019 game, Slay the Spire. Similar to Slay the Spire, the sequel has the user select one character, using and gaining cards to defeat monsters and complete encounters as they travel through multiple levels of the titular spire. Slay the Spire II introduces two new characters in addition to three returning characters, and introduces support for four player co-operative play.
An early access version of Slay the Spire II was released for Windows, macOS, Linux in March 2026.
At the start of the game, players select one of five characters, each with a different deck of starting cards and different pool of cards that can be gained throughout a run. These include three returning characters from Slay the Spire: the Ironclad, the Silent, and the Defect. Two all-new characters were also added: the Necrobinder who has a large skeleton hand companion called Osty, which can attack for the Necrobinder and shield incoming damage; and the Regent, who can forge a sovereign blade and use a unique resource called âÂÂstarsâ to play some cards.
Once a character has been picked, the player ascends multiple floors of a spire, with each randomly-generated act shown as a map with multiple routes to reach the act's boss. New in the sequel are alternate acts where each act has two different versions, randomly selected each run. Each environment offers a different range of enemies, events and bosses. Points on the map frequently are combat scenarios with monsters, but these can also include events, campfires where the player can rest and regain health, and a shop to buy or remove cards or acquire potions or artifacts. During combat, the player takes turns with the monsters. The player is informed of the planned attack each monster will make and takes actions during their turn, playing cards with the limited energy they get each turn. Cards include attacks, defensive moves, player buffs, enemy debuffs and other effects. Losing in combat ends that run, and the player must restart the climb of the spire. As part of the metagame, completion of runs, successful or not, can unlock entries on the new Timeline/Epoch feature, which presents the history of the titular Spire and how the playable characters came to encounter it, and is also used to unlock new characters and features in the game when certain metrics are met.
New to Slay the Spire II is a co-operative mode for up to four players. Each player uniquely selects one of the characters at the start, and during combat, they can apply any healing, defensive, or buffing or debuffing effect on their allies. Cards specific for multiplayer combat will also be available during these runs. Enemies have more health, and their attacks target all players as to offset the collective strength of the players' abilities. Otherwise, all players have their own set of health, cards, and resource pool during combat, and rewards and other choices are selected individually by players. If a player character loses their health, the combat continues with the remaining players, and after combat, that downed character will be revived with one hit point. The game ends if all cooperative players fall in combat.
After completing Slay the Spire, Anthony Giovannetti and Casey Yano, the founders of MegaCrit, created a number of small prototypes of games, not sure of their next planned title. As the COVID-19 pandemic hit, they wanted to start focusing on their next project, which came down to one of the prototypes that Yano had developed, and a sequel to Slay the Spire which Giovannetii had ideas for. Giovannetti said the choice came down to a coin flip, which the sequel won out.
The original game was developed in the Unity game engine by Unity Technologies, which MegaCrit had started using for the sequel. In September 2023, Unity Technologies announced a change to their runtime licensing code that was highly controversial but later reversed. When the runtime licensing change was announced, MegaCrit was one of the major indie studios that spoke out against it, and asserted they would no longer be using Unity for their game. They switched to the Godot engine shortly after this, having to update about two years' worth of development from Unity to the new engine.
One of the first patches made during the early access period, among other changes, removed a few cards that players had found capable of creating powerful gameplay loops. This change led to a review bombing of the game. Mega Crit released a second patch that brought back some of these cards, acknowledging the initial removal was not favorable and such changes are part of the goal of the early access period was adjusting cards and game tuning to keep the game's challenge.
Slay the Spire II was first announced in April 2024 with the intent to enter early access release by 2025. MegaCrit pushed off the early access release to March 2026 in September 2025 as "to make sure we're upholding the quality bar that both we and the gaming community have come to expect for early access titles". The game was available for early access release on March 5, 2026, for Linux, macOS and Windows. Mega Crit said that the early access version is mostly feature complete, using placeholder art for some of the newer cards and items in the game, and expect most of the early access period will be to balance the game.
In a similar phenomenon to the release of the highly anticipated ', the announcement of Slay the Spire II release date caused some indie developers to reschedule their releases to avoid their games getting lost in the coverage for Slay the Spire II. On its first day of early access release, Slay the Spire II reached over 177,000 concurrent players on Steam, beating previous records held by roguelike games Hades 2 and Mewgenics, as well as exceeding the player count for Bungie's Marathon released the same day. Concurrent player count had exceeded 400,000 by the following day. MegaCrit said that sales of Slay the Spire II within the first week of early access exceeded 3 million.