 Erik Wolpaw , National Lampoon veteran Jay Pinkerton and Left 4 Dead writer Chet Faliszek wrote the game 's script . Wolpaw and Pinkerton wrote the single @-@ player campaign story , while Faliszek wrote GLaDOS 's lines for the cooperative campaign . The game has 13 @,@ 000 lines of dialogue . The writers felt they needed to create a larger story for a stand @-@ alone title , and wanted the game to " feel relatively intimate " , and avoided adding too many new characters . They considered expanding the " sterility and dryness " of Portal and adding more comedy to the script . Wolpaw said that while some developers have been moving towards art games , no one had made a comedic video game . The game 's story development was tightly coordinated with the gameplay development and testing . 
