ArmA 2 mod turned standalone zombie apocalypse simulator DayZ has topped 800,000 sales less than a month after its Steam Early Access debut, an accomplishment that creator Dean Hall hopes will speed the game's ongoing development.

"We ([ArmA 2 developer Bohemia Interactive] and I) had very ambitious plans for 2014 already, however this amount of sales was completely unexpected," Hall said in a recent Reddit post shortly before DayZ hit the 800,000 sales mark. "Honestly, 250k within a quarter was what I would have considered a success. So to move nearly 800,000 in under a month is crazy." Hall's exuberance seems appropriate, given that less than a week ago the DayZ team was celebrating the sale of 400,000 copies of the game.

At a price point of $30 for the Steam Early Access version of the game, 800,000 copies sold adds up to $24 million. Even after you subtract the fees taken by Steam proprietor Valve Software, the cost of building the game, and other miscellaneous business expenses, that's a very sizable chunk of cash, which Hall believes will improve his team's ability to add new features to DayZ. "We'll be finalizing our roadmap in mid January, but it is safe to say that this kind of result will be having a very positive effect on that roadmap," Hall wrote.

This article was originally published on Joystiq.

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