In Slay the Spire players will regularly encounter hostile monsters which will engage them in combat.
Combat is done as a turn based card game. Players use cards from the deck the assembled during gameplay to perform combat moves, while monsters use a preset of skills to fight back.
Turn structure 
Edit
When in combat players move first.
At the start of each turn the player draws 5 cards from their deck and gain 3 energy. Then they have the opportunity to play any number of cards, provided they have enough energy left. Every card reads its energy cost and playing it consumes that amount of energy from the players energy pool.
Unless otherwise stated on the card, played cards are put on the discard pile after causing their effects.
During their turn players can also drink or throw potions at no cost.
Once players either have exhausted their resources or don't deem further actions beneficial, they can end their turn.
At the end of turn all remaining cards the players hand are discarded and their remaining energy is drained.
During the monsters' turn monsters use skills and attacks according to their intent, which players can see above their heads.
After all monsters have moved, it's the players turn again and the cycle continues until one party is defeated.
General Mechanics Edit
- HP - HP represents the health of the player and the opponents they encounter. Certain effects can reduce or increase the remaining and/or maximum HP of the player. HP persists throughout each Act of the game. After successfully defeating the Boss of an Act the player is fully healed. Once the remaining HP of the player reach 0 they die and the game is over.
- Damage - Attacks deal damage. Unblocked damage results in loss of HP.
- Block - Block applies shields to any combatant for one turn of combat. The intensity of the shields determines how much damage it can take before breaking. Whenever a blocking target receives damage the shields are reduced first. Once an attack exceeds the shield intensity it breaks and the target starts taking HP damage. Unless prevented by other means all applications of Block are removed at the start of each turn in combat.
Combat Conditions Edit
During Combat both players and their opponents can be affected by a number of conditions both beneficial and detrimental:
General Conditions
Condidtinos that can affect both players and monsters:
| Name | Symbol | Description | Stacking | Notes |
|---|---|---|---|---|
| Weakend | This unit deals 25% less damage with attacks | Duration | ||
| Vulnerable | This unit receives 50% more damage from attacks | Duration | ||
| Strength | This unit deals X additional damage with attacks | Intensity | Can be negative, resulting in damage reduction. | |
| Artifact | Negates X incoming debuffs | Intensity | ||
| Thorns | Deals X damage to any attacker | Intensity | Attackers that hit multiple times will receive recoil damage for each individual hit. | |
| Barricade | Prevents removal of Block at the start of turn | None | ||
| Metallicise | This unit gains X Block at the end of their turn | Intensity | ||
| Plated Armor | This unit gains X Block at the end of their turn. Taking unblocked damage removes one application of Plated Armor | Intensity | Attackers that hit multiple times will remove 1 application for each individual hit. | |
| Intangible | All incoming damage and life loss is reduced to 1 | Duration |
Player exclusive
Conditions (excluding unique effects from Powers) that can only affect players (so far):
| Name | Symbol | Description | Stacking | Notes |
|---|---|---|---|---|
| Frail | This unit applies 25% less block with cards | Duration | ||
| Dexterity | This unit applies X additinoal block with cards | Intensity | Can be negative, resulting in application reduction. | |
| Entangled | This unit cannot play Attack cards | Duration | ||
| Flex | This unit loses X strength at the end of turn | Intensity | Opposite to Shackled | |
| Blur | Block is not removed at the beginning of the next X turns | Duration | ||
| Draw reduction | Draw 1 less card at the start of the next X turns | Duration |
Monster exclusive
Conditions that can only affect monsters (so far):
| Name | Symbol | Description | Stacking | Notes |
|---|---|---|---|---|
| Minion | This unit abandons combat if only minions remain | None | Minions are summoned by certain Bosses and Elites to aid them in combat.
In order to prevent loopholes certain effects don't work on minions. | |
| Poison | This unit loses X HP at the start of each turn and then removes 1 application of poison. | Intensity | ||
| Shackled | This unit regains X Strength at the end of turn | Intensity | Opposite to Flex |
