 Portal 2 's lead writer Erik Wolpaw estimates each campaign to be about six hours long . Portal 2 contains in @-@ game commentary from the game developers , writers , and artists . The commentary , accessible after completing the game once , appears on node icons scattered through the chambers . According to Valve , each of the single @-@ player and cooperative campaigns is 2 to 2 @.@ 5 times as long as the campaign in Portal , with the overall game five times as long . 
