 Sixense developed a version of Portal 2 to support the Razer Hydra motion controller for PC that allows enhanced control of some game elements . Ten extra single @-@ player levels are available as downloadable content for this version . Writer Chet Faliszek said Sixense developers spent nine months to a year in @-@ house at Valve preparing the native version . A limited edition of the Razer Hydra comes bundled with a copy of Portal 2 for PC . 
