Moon Sweepers multiplayer: 16-player co-op rules

How large can a lobby be?

Steam store text: team up in online co-op lobbies of up to 16 players. Games Press repeats “single-player and online co-op for up to 16 players.” Spread out to cover more ground or clean the same area together — both play patterns are described in marketing copy.

There is no official console cross-play listing because the game itself is Windows Steam-only in the sources we opened. See platforms.

Are upgrades shared?

Upgrades (since 1.0.3): the whole crew uses the host’s upgrade matrix, and anyone’s purchase upgrades everyone. Older saves keep the highest level anyone had bought. That means one player buying a tool tier advances the shared tree. The official 1.0.3 notes announce this upgrade-sharing rule; they do not separately document a shared-money claim.

If you host, expect your upgrade state to be the template other players join into after 1.0.3.

Can the host moderate the lobby?

Yes, since 1.0.3. Open ESC → Your Crew to see the lobby roster. From there the host can remove a player temporarily (kick) or permanently for that save (ban); a ban lifts only when the host unbans them in the same menu.

What did 1.0.4 change for multiplayer feel?

Patch 1.0.4 multiplayer section highlights:

• Ground sync rework so every client shows the same cleaned terrain (player sweeps and robot trails included — no dust popping back)
• Shared belt building: crewmates may add splitters or mergers onto belts someone else already placed
• Mergers now alternate between their inputs

These are quality and sync fixes, not a change to the 16-player cap.

Version matching and saves

The 1.0.3 notes state: all crewmates must be on version 1.0.3 to play together. The 1.0.3 notes require everyone on the same version; check each later patch’s notes. 1.0.4 also warns that saves made in 1.0.4 cannot be opened in older versions.

Backup path documented in 1.0.4 (outside Steam Cloud):
C:\Users\[user-name]\AppData\LocalLow\DragDropGames\MoonSweepers\Backups

Solo versus co-op choice

Solo is officially supported. Co-op shines when you want parallel cleaning or shared factory work, but it also shares progression decisions. New players can learn the loop alone using the beginner guide before opening a 16-player lobby. After a session, skim patch notes so everyone installs the same build.

Sources and verification

Checked October 27, 2026.

• Steam store — Online Co-op / About text
• Games Press player count
• 1.0.3 Patch
• Developer message (shared upgrades callout)
• 1.0.4 Patch

Game imagery © DragDrop Games.