Can't invite a friend on another platform? That's a confirmed bug, not your setup — crossplay works, the invite button doesn't. Patch 1.01 shipped session passwords as the fix; here's how to use them, plus the three other causes of a failed join. Read the fix
- ✓ Crossplay across Steam, Epic, the Microsoft Store PC app, PS5 and Xbox at launch
- ✓ 1–4 player online co-op; contract difficulty scales with human player count
- ✓ Built-in proximity voice chat, plus push-to-talk added in the launch update (voices come from where players stand)
- ✓ Solo play with AI companions, and offline play is supported
- ✗ Cross-progression (saves moving between platforms)
- ✗ Couch, split-screen or LAN co-op — online co-op only
- ✗ PvP of any kind (the devs say "maybe someday" if demand is loud)
Co-op is the point of this game, and the design keeps saying so. Voice chat is proximity-based: your crewmate's voice comes from where they're standing and fades with distance, which is exactly the channel the sanity systemloves to poison — hallucinations can distort what you hear, and a "teammate" calling you over may not be one. Running Discord instead sidesteps the horror and, honestly, half the game.
How a four-player expedition divides
Crews that survive specialize — you pick from ten-plus playable explorers, then the contract fixes your weapon pool, so decide aboard the Tempestad who carries the loud gun, who carries Ammonia Saltsfor revives, who handles light, and who walks point with a melee weapon that doesn't wake the forest. The golden rule is proximity: the Prowler only takes explorers who wander alone, and sanity drains faster in isolation.
Playing solo
Solo expeditions ship with AI companionsby default, and contract difficulty scales to the human player count. A toggle to switch the companions off isn't exposed in the demo — it's one of the community's louder requests, and we re-check at launch. What doesn't scale is epistemology: nobody can cross-check your hallucinations. When the gun in your hands looks like a wooden stick, a crewmate can tell you it isn't. Alone, you find out the hard way. Offline play is supported too — the PlayStation listing marks online as optional.
Where to next
Session passwords, the beta-branch trap and the other causes.
What 1.01 changed for finding friends.
Platform details and store info.
Play Anywhere, optimisations and store info.
The honest read on handheld performance.
Every quick answer in one place.
Crossplay questions
Is The Mound: Omen of Cthulhu crossplay?
Yes. Crossplay is supported at launch across Steam PC, PlayStation 5 and Xbox Series X|S — mixed-platform crews can play together from day one.
Does The Mound have cross-progression?
Not confirmed. Crossplay (playing together) is in; carrying your own save between platforms has not been announced.
Is The Mound couch co-op or split screen?
No — co-op is online only, for one to four players.
Does The Mound have voice chat?
Yes, built-in proximity voice chat: voices are spatial and fade with distance. The sanity system can distort what you hear, which is very much intended.
How many players is The Mound co-op?
One to four players in online co-op, with contract difficulty scaling to the human player count. Mixed-platform crews work at launch thanks to crossplay.
Can you play The Mound solo?
Yes — solo expeditions ship with AI companions by default, difficulty scales down, and offline play is supported. A companion-disable toggle isn't exposed in the demo (players are asking for one). Nobody can cross-check your hallucinations alone, which is the intended cost.
Is The Mound cross platform?
Yes — cross platform play (crossplay) is confirmed at launch across Steam, Epic, the Microsoft Store PC app, PS5 and Xbox Series X|S. Cross-progression (shared saves between platforms) is the part that has not been announced.
Is there matchmaking or a server browser?
Yes — an online server list you join open expeditions from; you don't need a pre-made squad. Patch 1.01 (July 21) added a server setting to find a session using a password, which is now the reliable way to land in a specific friend's lobby rather than scrolling the public list.
How do I play with friends on a different platform?
Crossplay works; the in-game invite button is what's broken across platforms — it only lists people on your own platform. Since patch 1.01 the host sets a password on their session and shares it, and everyone joins with that. Everyone needs to be on 1.01 or newer for the option to exist.
Can you communicate without voice chat?
The launch update added push-to-talk on top of proximity voice. There's still no emote wheel or ping system — a common request — so mute players want a crew that watches body language: crouch-spam is the unofficial 'follow me'.