 On April 1 , 2011 , Valve released another alternate reality game called the Potato Sack . Players tried to solve the multi @-@ tiered puzzle , coordinating efforts through web sites and chat rooms . Some journalists believed the game denoted the release of Portal 2 on April 15 , 2011 , instead of the target release date of April 19 , 2011 . On April 15 , the players discovered " GLaDOS @ Home " , a distributed computing spoof that encouraged participants to play the games to unlock Portal 2 early . Once the puzzles were solved , Portal 2 was unlocked about ten hours before its planned release . 
