Official player count and modes
The official Steam description defines 1–4 players as the native range. Its current feature record lists Single-player, Multi-player, Co-op and Online Co-op. That is the supported answer for the base game; it is not a live count of people currently online.
Host a game
Open Multiplayer and choose Host Game. The official English interface includes Copy Lobby ID and Invite Friend actions for an active lobby. Share the lobby ID only with the people you want to join.
These labels establish the official lobby entry points. They do not prove that every firewall, router or Steam session will connect, so this page does not invent ports, NAT settings or generic connection fixes.
Join a game
Choose Join Game. The current interface provides Find Steam Friends and Join By ID choices. Use the friends option when the host appears through Steam, or use the lobby ID copied by the host.
Local play and more-player mods
Steam currently advertises Online Co-op, but its feature snapshot does not list Shared/Split Screen or Remote Play Together. That absence is not turned into a permanent “impossible” claim; it means this guide does not label couch co-op as officially supported.
The official player range stops at four. Search results do surface community interest in more-player mods, but this evidence pass did not verify a current mod build, its limit or a reproducible installation path from a primary source. Any modified player cap is therefore outside official support and intentionally omitted here.