The number, and where it comes from
Four is the ceiling. It is worth being precise about the source, because Steam does not actually print it: the store page lists Single-player, Multi-player, Co-op and Online Co-op as categories, with no player count attached to any of them.
The four comes from the publisher’s launch press release, which outlets reprinted in identical wording — “You can play solo or team up with up to four players online”. Both reprints are linked at the foot of this page so you can check the sentence yourself. That is the publisher’s own copy, so it is reliable; it simply is not a line on the Steam page, and we would rather tell you which document it came from.
What changed on 12 August
Most pages answering this question were written in the game’s first week, when starting a session meant inviting someone you already knew. That stopped being true on 12 August.
- “Public servers are now available to join via an in-game browser.”
- “Added more host game settings under the multiplayer options tab.”
- “Added support for password protected servers.”
- “The friends only and invite only privacy mode now allows for friends of anyone in the server to join, not just the host.”
That last line is easy to skim past and it changes how groups actually form. Previously a friends-only lobby meant the host’s friends. Now anyone in the session can pull in their own friends, so a group of four can assemble through two people who have never met.
Two days earlier, patch 1.04 had already handed hosts the controls:
- “Added multiplayer settings for lobby privacy and max player count.”
- “Added a view lobby menu where you can adjust player mic volume and kick / ban players.”
So the host sets the cap, and can run a session below four deliberately.
Your four ways to fill a lobby
- Public server browser — open the in-game browser and join a listed session. This is the route that did not exist before 12 August.
- Password-protected server — public listing, private entry. Useful for a community or a group organising outside the game.
- Friends-only — now includes friends of everyone already in the session, not just the host’s.
- Invite-only — the most controlled option, and still supported. The developers stated in the 12 August roadmap post that friends-only and invite-only “will remain available for players who want a more controlled experience.”
Solo is a real option, not a fallback
Single-player is a listed category, not an accident of letting you launch alone. The studio has also spoken directly to it: in a June developer message they wrote that they want the game “challenging, tense, and rewarding” but not “unnecessarily punishing, especially for solo players and smaller groups”, and that they were watching feedback and gameplay data on exactly that.
Community Players broadly report solo being harder rather than impossible — noise management matters more when nobody else can pull attention, and hauling is slower with one pair of hands. Treat that as the room’s consensus, not a measured claim.
What is still missing
No local or split-screen play. No console versions, so no crossplay question to answer. More host tools are officially in progress — the roadmap post says the studio is “working on more tools to help hosts manage their sessions” — see the full roadmap.