How to Play Co-op in Backrooms Lost Runners: The Definitive Guide

To play co-op in Backrooms Lost Runners, one player must host a private lobby from the main menu and invite friends directly through the Steam overlay. There is no public matchmaking or server browser; the multiplayer experience is designed exclusively for a pre-made group of up to four players. This guide breaks down the exact steps for both the host and joining players, along with essential tips for surviving the buzzing mono-yellow hellscape as a team.

01

Setting Up Your Private Lobby (Host's Guide)tag

Hosting a game is straightforward, but it relies entirely on Steam's social features running correctly. Before you begin, ensure your Steam client is up to date and your in-game overlay is enabled. The player with the most stable and fastest internet connection should always be the host to minimize lag and desynchronization for the rest of the team.

Step 1: Navigate to the Private Game Menutag

From the main menu of Backrooms Lost Runners, you'll see a few options. Ignore 'Public Game'—as of the latest patch, this feature is not implemented. Your only path to multiplayer is a private, invite-only session.

1. Click Play on the main menu.
2. Select the Private Game option. This will create a lobby that is invisible to anyone not on your friends list.

This action designates you as the server host. The game will load you into a pre-game staging area, where you can wait for your friends to join before venturing into Level 0.

Step 2: Invite Friends Through the Steam Overlaytag

With your private lobby active, it's time to bring in your team. The game does not have its own in-game invitation system, so you'll use the universal Steam overlay.

1. Press Shift + Tab to open the Steam overlay.
2. Navigate to your Friends List.
3. Find the friend(s) you want to invite. Right-click their name.
4. From the dropdown menu, select Invite to Game.

Your friend will receive a pop-up notification from Steam with an invitation to join Backrooms Lost Runners. Once they accept, they will begin loading into your lobby. You can repeat this process for up to three other players, for a maximum team size of four.

02

How to Join a Friend's Gametag

If you're not hosting, your role is even simpler. As long as you have the host on your Steam Friends List, you can join their game in a couple of clicks. Make sure you have the game launched before accepting the invite to ensure a smoother process.

When the host sends the invitation, you will receive a standard Steam game invite notification, usually accompanied by a sound. Click the 'Accept' button on this pop-up, and Steam will automatically launch you into their game session.

Alternatively, if you miss the pop-up, you can join through the Friends List:

1. Open your Steam Friends List (either in-game via the overlay or on your desktop).
2. Find the host's name. They should have a status indicating they are playing Backrooms Lost Runners.
3. Right-click their name and select Join Game.

If the 'Join Game' option is greyed out, it could mean their lobby is full, they are in a loading screen, or a bug is preventing the connection. Have the host try re-sending the invitation as a first step.

03

Key Co-Op Gameplay Changes You Need to Knowtag

Playing with friends isn't just about having backup; the game's core mechanics shift to accommodate multiple players. Going in with a solo mindset is a recipe for a quick team wipe. The most significant change is that all pickups—batteries, Almond Water, files—are shared. They are not instanced per player. If one person grabs a battery, it's gone for everyone else. This makes communication and resource management paramount.

Another critical factor is the proximity voice chat. Your ability to communicate with your team is limited by your distance from them in-game. Stray too far, and your comms will cut out, leaving you isolated. This mechanic actively discourages splitting up and reinforces the need to stick together. Finally, the Entities are more aggressive and have slightly altered behavior with more players present, often creating chaotic situations where multiple threats must be managed simultaneously.

04

Troubleshooting Common Connection Problemstag

Sometimes, the connection between the liminal space and your friend's PC just doesn't want to cooperate. Most issues stem from the Steam overlay or network configurations. Here are the most common problems and their solutions.

• Invite Not Received: The most common culprit is a disabled Steam overlay. The joining player should go to Steam > Settings > In-Game and ensure "Enable the Steam Overlay while in-game" is checked. Both players should then restart the game.
• "Host Not Responding" Error: This often points to a firewall issue on the host's end. The host should ensure Backrooms Lost Runners is allowed through their Windows Defender Firewall or any third-party antivirus software. Adding an exception for the game's executable (.exe) file can resolve this.
• Extreme Lag or Desync: If players are teleporting or actions are severely delayed, the host's internet connection is likely struggling. There is no fix for this other than having the player with the best (lowest latency, highest upload speed) connection host the game.
• Game Crashes on Join: This can happen if a player's game files are out of sync with the host's. All players should right-click the game in their Steam Library, go to Properties > Installed Files, and click "Verify integrity of game files..." to fix any corrupted data.

05

Frequently Asked Questionstag

Let's clear up some common questions about the multiplayer experience.

How many players can play co-op in Backrooms Lost Runners?tag

You can play with a maximum of four players in a single co-op session (one host and three other players).

Is there split-screen or local co-op?tag

No, Backrooms Lost Runners does not support local or split-screen co-op. The multiplayer mode is online-only and requires each player to own a copy of the game and have a separate device.

Does my progress in a co-op game save?tag

Progress, such as reaching new levels or completing objectives, is tied to the host's session. When you join a friend's game, you are effectively playing in their save file for the duration of that session. Any major progression is saved for the host.

Can I join a game that is already in progress?tag

Yes, you can join a co-op game that is already underway, provided the host sends you an invite and there is an open slot in the lobby (fewer than four players).

06

Final Thoughtstag

Playing Backrooms Lost Runners with friends transforms the isolating horror into a chaotic, communication-driven survival challenge. While the lack of public matchmaking may be a drawback for some, the friends-only system ensures a more coordinated and less grief-stricken experience. The key is a stable host and clear communication, especially when resources are scarce and the buzzing of the lights is drowned out by the sound of something skittering just out of view. Stick together, call out supplies, and you might just survive to see the exit.