 The designers built several of Portal 2 's early chambers by applying decay , collapse , and overgrowth to Portal chambers to give Portal players a sense of nostalgia and a sense of time passed in the game 's world . The design team replaced low resolution textures from the first game with higher @-@ resolution , dirty textures that the new game engine could support . The middle section of the single @-@ player campaign takes place in large in @-@ game spaces in which most surfaces are unable to accept portals , which forces players to find creative ways to cross them . Much of the architecture in these sections was inspired by photographs of industrial complexes , including CERN , NASA , and the abandoned Soviet space program . According to writer Jay Pinkerton , in the game 's final section , in which Wheatley controls the Aperture facility , " the level designers just had a blast " creating deranged chambers reflecting Wheatley 's stupidity . The designers recognized that solving puzzles would mentally tire players , so they inserted occasional " experiences " to provide a respite and to advance the plot . 
