Portal

Portal  is a 2007  puzzle - platform game  developed and published by  Valve . It was released in a  bundle ,  The Orange Box ,  for  Windows ,  Xbox 360  and  PlayStation 3 , and has been since ported to other systems, including  Mac OS X ,  Linux ,  Android  (via  Nvidia Shield ), and  Nintendo Switch . Portal  consists primarily of a series of puzzles that must be solved by teleporting the player's character and simple objects using "the Aperture Science Handheld Portal Device", often referred to as the "portal gun", a device that can create inter-spatial portals between two flat planes. The player-character,  Chell , is challenged and taunted by an  artificial intelligence  named  GLaDOS  (Genetic Lifeform and  Disk Operating System ) to complete each puzzle in the  Aperture Science Enrichment Center  using the portal gun with the promise of receiving cake when all the puzzles are completed. The game's unique physics allows kinetic energy to be retained through portals, requiring creative use of portals to maneuver through the test chambers. This gameplay element is based on a similar concept from the game  Narbacular Drop ; many of the team members from the  DigiPen Institute of Technology  who worked on  Narbacular Drop  were hired by Valve for the creation of  Portal , making it a  spiritual successor  to the game. Portal  was acclaimed as one of the most original games of 2007, despite criticisms for its short duration and limited story. It received praise for its originality, unique gameplay and dark story with a humorous series of dialogue. GLaDOS, voiced by  Ellen McLain  in the English-language version, received acclaim for her unique characterization, and the end credits song " Still Alive ", written by  Jonathan Coulton  for the game, was praised for its original composition and humorous twist.  Portal  is often cited as one of the  greatest video games ever made . Excluding Steam download sales, over four million copies of the game have been sold since its release, spawning official merchandise from Valve including plush Companion Cubes, as well as fan recreations of  the cake  and portal gun. A standalone version with extra puzzles,  Portal: Still Alive , was also published by Valve on the  Xbox Live Arcade  service in October 2008 exclusively for Xbox 360. A sequel,  Portal 2 , was released in 2011, which expanded on the storyline, adding several gameplay mechanics and a cooperative multiplayer mode.