 Portal 2 was officially announced on March 5 , 2010 , via Game Informer . Events during the preceding week foreshadowed the announcement . On March 1 , Valve released a patch for Portal that included a new achievement , " Transmission Received " , requiring the player to manipulate in @-@ game radios . This revealed new sound effects that became part of an alternate reality game ( ARG ) . The new effects included Morse code strings that suggested GLaDOS was rebooting and <unk> images from a grainy Aperture Science video . The images included hints to a BBS phone number that , when accessed , provided a large number of ASCII @-@ based images relating to Portal and segments of Aperture Science documents . Many of these ASCII pictures were later published in the Game Informer reveal of the title . New ASCII images continued to appear on the BBS after the official announcement . Background on the ARG is embedded in additional <unk> images found in a hidden room in Portal 2 . Valve 's Adam Foster came up with the idea for the ARG , tying it to the Game Informer reveal , and he provided his own home phone line to run the BBS software on , as Valve 's offices at the time were too modern to support the protocol . Foster estimates the ARG cost less than $ 100 to run . 
