Enemy HP by player count
In co-op, enemy HP is multiplied by the number of players and by a factor for the act. Enemies start the fight at the new max HP.
| Act | Factor | 2 players | 3 players | 4 players |
|---|---|---|---|---|
| Act 1 | 1.1 | ×2.2 | ×3.3 | ×4.4 |
| Act 2 | 1.2 | ×2.4 | ×3.6 | ×4.8 |
| Act 3 | 1.2 | ×2.4 | ×3.6 | ×4.8 |
| Act 3 boss | 1.3 | ×2.6 | ×3.9 | ×5.2 |
The number of enemies does not change. See also the co-op explorer.
Enemy Block and powers
Block that enemies gain from their moves is multiplied the same way. So are these enemy powers: Artifact, Curl Up, Flutter, Hardened Shell, Plating, Plow, Rampart, Reattach, Regen and Shriek.
Cards only in co-op
These cards appear only in multiplayer runs:
| Pool | Cards |
|---|---|
| Colorless | Beacon of Hope, Believe in You, Coordinate, Gang Up, Huddle Up, Intercept, Knockdown, Lift, Mimic, Rally, Tag Team |
| Ironclad | Demonic Shield, Tank |
| Silent | Flanking, Sneaky |
| Defect | Energy Surge, Ignition |
| Regent | Hammer Time, Largesse |
| Necrobinder | Glimpse Beyond, Legion of Bone |
The Silent's Well-Laid Plans appears only in single-player runs. Every other card appears in both.
Shorter maps
Every act has one room fewer in multiplayer. Relics that stop appearing before the act 3 treasure chest check for floor 38 in co-op instead of floor 41.
Rewards and relic chests
Each player gets their own card, potion and relic rewards from their own random stream, so two players who win the same fight see different rewards. Fight gold works the same way as in single player.
At a treasure chest each player picks a relic:
- A relic only one player picked goes to that player.
- If several players pick the same relic, they play a random rock, paper, scissors round and the winner takes it.
- Players who lost get one of the relics nobody picked, at random, while any remain.
- A player who skips gets nothing.
For how the seed and random streams work in co-op, see Slay the Spire seeds.