Split-screen on PC

Portal 2

Up to 2 players on one PC, with controllers, keyboard and mouse or several keyboards and mice.

2Verified handler

Handler “Portal 2” by ksagaming, version 2

What works

With Nucleus Co-op, up to 2 players can play Portal 2 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 “Portal 2” by ksagaming does the setup and was checked by hub moderators: version 2, updated 25 Oct 2025. Portal 2 is a platformer, puzzle and adventure game from 2011.

Players2
ControllersSupported
Keyboard and mouseSupported
Several keyboards and miceOne per player
Hub moderatorsVerified

How to play Portal 2 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 Portal 2 handler
In Nucleus Co-op, search the Hub for Portal 2 and install its handler, or download the handler file from this page and drop it on the Nucleus window. Then show Nucleus where Portal 2 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 Portal 2 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
Portal 2 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 2 copies
Each player runs their own copy of Portal 2, 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

This handler allows for proper progression, multiple keyboards/mice and monitors, unlike the built in split-screen.

To play start the handler then press the END key once to lock input once both instances load, select play co-operative game and one player should invite the other to start playing, press End once finished to unlock inputs. In-game click once on an instance with your mouse if the camera starts moving continuously to fix it.

Based on the Left 4 Dead 2 handler by Talos91 who also helped fix some issues with this handler so thanks to him and to all the testers from the Nucleus discord.

About Portal 2

Sequel to the acclaimed Portal (2007), Portal 2 pits the protagonist of the original game, Chell, and her new robot friend, Wheatley, against more puzzles conceived by GLaDOS, an A.I. with the sole purpose of testing the Portal Gun's mechanics and taking revenge on Chell for the events of Portal. As a result of several interactions and revelations, Chell once again pushes to escape Aperture Science Labs.

Summary from IGDB