Test Chamber 8 - Course 2 - Mass and Velocity - Co-op Challenges | Portal 2 | Gamer Guides®
Guide for Portal 2 - Co-op story walkthrough
Giant Fan (Portal 2) - Valve Developer Community
In Portal 2's CO-OP hub just before the DLC course's disassembler, there's this other monitor that asks you to select a course, however, to this day the only one you can select
Portal 2 was released a decade ago, so here are 10 facts about Valve's classic puzzle game | Rock Paper Shotgun