After one year on sale. http://www.bit-tech.net/news/gaming/2014/10/23/the-stanley-parable-hits-1-million-sales-mi/1
I loved the game, haven't laughed so much in a game for a long time (the store cupboard was a particular highlight for me). So glad it's sold well, it's nice to play a game that doesn't follow conventional rules.
Most enjoyable game I played this last year. One of the most enjoyable games I've ever played. A must own, must play title. There's nothing like it. Stanley didn't buy this title. Even though he knew he really should. Stanley often searched for games, hovering his finger over the buy button. Stanley never knew why he wasted his time, as he never purchased it. It was like a game to him. He could easily win by pressing the button. But he still never pressed it.
I've played the mod, loved the demo, and I bought the full version as well. I've played it through a couple of times, bit haven't played it for a while because I've been making some progress on the 'go outside' achievement.