The Stanley Parable sold over 100K copies in three days
Wreden explained in a postmortem that he owes much of its success to its bizarre marketing campaign that showed nothing of the final game. "We released five trailers over the course of the game's development, and not one of them contains any substantial actual footage of the game," he said. "If you make the marketing material interesting on its own, it's irrelevant whether it 'sells' your game. Our focus was always on creating content that was on its own fun for people to experience and to be a part of, with essentially zero per cent of the design aimed at trying to get the game to sell."
http://www.eurogamer.net/articles/2013-10-22-the-stanley-parable-sold-over-100k-copies-in-three-days