 Valve considered adding a competitive mode to Portal 2 . According to Wolpaw , the mode was similar to the video game Speedball ; one team would try to transport a ball from one side of the playing field to the other using portals , while the other team would attempt to stop them with their own use of portals . Matches would commence with this objective in mind , but quickly descended into chaos . Valve realized that people enjoyed solving puzzles with portals more and therefore they focused on the cooperative mode . 
