

Source Engine games will usually not let you launch more than one instance.

Launch the shortcut as many times as you need.You can remove it if you want, but it is risky. The -insecure will prevent you from joining any Valve Anti Cheat (VAC) secured servers.You can adjust the width/height for your monitor. At the end of Target, add -windowed -w 1920 -h 500 -insecure +m_rawinput 1.Right-click the new shortcut and select properties. Right-click hl2.exe and click Create shortcut. Open the GarrysMod directory by right-clicking Garry’s mod in Steam -> Properties -> Local files -> Browse game files… In options, load the Source Engine preset.Install and run Universal Split Screen: see the quick start guide.
