Amnesia: The Dark Descent has sold more than 1.4 million copies, according to developer Frictional Games.
Much of that figure comes from the company's participation in the Humble Indie Bundle this year and Steam's Potato Sack Bundle last year.
"Despite that huge number of sales, what I think is more interesting is how good the monthly sales still are," wrote the developer on its blog. "Not counting any discounts, the monthly full price sales lie at over 10,000 units. This means that less then every 5th minute someone in the world is buying a copy of Amnesia. This is totally insane to me.
"The figures themselves are far beyond any guesses we would have made two years ago. It is also insane because this number is actually higher than it was around three months after initial launch."
Frictional contributes the success to the game's unique concept ("horror games without combat do not really exist on PC"), the modding community, and a steady stream of YouTube clips.
Piracy is not a concern for the developer, which is now producing Amnesia: A Machine for Pigs, a sequel to The Dark Descent that Thechineseroom is developing.
Frictional Games now employs 11 people.
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