Newell: Portal 2 Has Sold 3 Million Copies
Newell used the number as evidence that a game can be commercially successful and educational, going on to cite Portal 2's use as by educators to teach lessons about physics.
Portal 2 finished second to Warner Bros.' Mortal Kombat reboot in U.S. new retail sales across all platforms in its premiere month, according to NPD. The title fell to fourth place in those same rankings for May.
The game also led the UK's mulitplatform sales charts for two weeks after its release, before being unseated by exercise title Zumba Fitness.
Critics were overwhelmingly positive when writing about Portal 2, praising the game's inventive puzzles, original story and an attractive co-operative mode.
The original Portal sold over 4 million copies at retail, plus an unspecified number of Steam sales since its release in 2007.