Split-screen on PC

Whisper Mountain Outbreak

Up to 4 players on one PC, with controllers, keyboard and mouse or several keyboards and mice.

4Verified handler

Handler “Whisper Mountain Outbreak” by Talos91, version 1

What works

With Nucleus Co-op, up to 4 players can play Whisper Mountain Outbreak together on one PC, each in their own part of the screen, with controllers, keyboard and mouse or several keyboards and mice. The free community handler “Whisper Mountain Outbreak” by Talos91 does the setup and was checked by hub moderators: version 1, updated 20 May 2026. Whisper Mountain Outbreak is a tactical, adventure and indie game from 2025.

Players4
ControllersSupported
Keyboard and mouseSupported
Several keyboards and miceOne per player
Hub moderatorsVerified

How to play Whisper Mountain Outbreak split screen on PC

Get Nucleus Co-op
Download Nucleus Co-op, free for Windows 10 and 11, and unzip it into its own folder, for example C:\NucleusCo-op. There is no installer.
Keep it out of Program Files, your user folder and OneDrive.
Download Nucleus Co-op
Install the Whisper Mountain Outbreak handler
In Nucleus Co-op, search the Hub for Whisper Mountain Outbreak and install its handler, or download the handler file from this page and drop it on the Nucleus window. Then show Nucleus where Whisper Mountain Outbreak is installed.
Download the handler file (.nc)
Take a seat
Each player presses a button on their own controller to join and takes a spot on the screen. Pick a layout that fits your players.
Playing with several keyboards and mice? Press End once everything is in place to give each window its own cursor.
Launch and connect
Press Launch: Nucleus opens one copy of Whisper Mountain Outbreak per player and lays the windows out on your screen. Then link them in game, usually one player hosts a LAN or online session and the others join it. The handler notes say how.

What you need

A Windows 10 or 11 PC
Nucleus Co-op runs on Windows only. System requirements
Whisper Mountain Outbreak for Windows
Installed on that PC. Nucleus starts every player's window from that one install.
Nucleus Co-op, free
With .NET Framework 4.7.2 or later and the Visual C++ 2015–2022 runtimes (x86 and x64). Download
Something to play with
One controller per player, or one keyboard and mouse per player. Controllers · Keyboards and mice
A PC that can run 4 copies
Each player runs their own copy of Whisper Mountain Outbreak, so the PC carries several times the usual load. Lower the graphics settings if it struggles. Performance tips
A multiplayer mode
Nucleus links the windows through the game's own LAN or online mode; the handler takes care of it.

Handler notes

Tested and working with latest legit Steam version. Connecting the instances requires internet connection and could break if the devs block this from their servers so try it while it still works.
Split-screen setup guide.
Create a private co-op room in one instance and join in the others with the invite code.
If you use gamepads click with your main mouse cursor on each window for they to work correctly. If you use keyboards/mice after all the instances have launched, resized and positioned correctly, press the END key once to lock the input for all instances to have their own working cursor and keyboard, you need to left click each mouse to make the emulated cursors appear after locking the input. Press the END key again to unlock the input when you finish playing.
Read the FAQ if you have any further questions and want to know more about Nucleus Co-op.
Handler by Talos91. Support the Nucleus Co-op team if you love the project.

About Whisper Mountain Outbreak

An isometric co-op PvE multiplayer survival horror game. It's 1998, and an ancient curse has been unleashed, trapping everyone on Mt. Bisik. When a mysterious fog appeared, people started hearing whispers and seeing monsters. Fight, explore, solve puzzles, and figure out a way to escape... together!

Summary from IGDB