The quick answer

Slay the Spire 2 supports online co-op for up to four players total. Mega Crit says multiplayer uses your Steam friends list and has no matchmaking. Solo play is also available.

That makes this a game to arrange with a group you already know. The official screenshot below shows a shared battle; it does not show how to create or join a lobby.

Four Slay the Spire 2 characters facing a Terror Eel, with the active player's card hand below
Four characters face a Terror Eel in Mega Crit's official co-op gameplay screenshot. This illustrates a battle, not an invitation-menu procedure.Mega Crit · Official image source · View full size

Source: Mega Crit FAQ · Early Access launch announcement

Which platforms are confirmed?

Mega Crit's published platform position, checked October 19, 2026:

PlatformOfficial position
Windows, macOS and LinuxAvailable through Steam Early Access.
Steam DeckCompatibility confirmed by Mega Crit.
Console and mobilePorts are anticipated after Early Access; no fixed release date is given.

Source: Mega Crit FAQ

Before your group starts

Editorial planning suggestions:

  1. Confirm the guest list. A fifth person cannot fit into one four-player run, so agree on separate groups or another time before anyone waits in a call.
  2. Exchange Steam profiles and identify the correct accounts. If someone is buying the game for this session, have them check the official store's system requirements first.
  3. Agree whether to discuss card choices or let each player discover them. Set a stopping time and decide how much explanation newcomers want.

Source: Official Steam listing and requirements

What Early Access includes

The live Steam listing describes five playable characters, solo and online co-op play, and multiplayer-specific cards. Mega Crit's launch post also highlights combinations between teammates.

AvailableDeveloper plans
The current playable game and its co-op systemsMore content, a full ending, additional modes and continued balance work.
Features described in the current Steam listingNo firm full-release date in these sources.

Source: Steam Early Access description · Mega Crit launch announcement

Sources & scope

This article summarizes the official material linked below. It is not a hands-on review. Screenshots are credited to their original publishers; they are not evidence that we tested these steps. Game details can change after publication.

Sources checked: 19 Oct 2026. Read how we use sources and AI assistance.