Co-Optimus - News - Valve Updates Portal 2 With an Official PC Split-Screen Co-Op Mode
33 Best split-screen PC games as of 2023 - Slant
The best split-screen games for PC | Digital Trends
Uhh wtf? What's happening here? (Portal Reloaded coop in split screen, as I can't find ppl. btw it's so damn confusing, and I've played the whole singleplayer campaign...) : r/Portal