DayZ, the open-world zombie adventure game that has captured the imagination of gamers across the world, has set a new milestone for sales, hitting 800,000 copies, according to Dean Hall.

In a Reddit post Hall was asked about how the influx of cash from sales of the game since DayZ was released on Dec. 16, 2013  — which is being reported at $12 million — will affect the plans for the game. Hall said he and publisher Bohemia are blown away by the success of the game.

"We (Bohemia and I) had very ambitious plans for 2014 already, however this amount of sales was completely unexpected. 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. 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.

While the early success of the game is confirmed, there is plenty of work to be done on the game before the DayZ standalone is finalized and the official full version of the game is available. According to Bohemia, there is still plenty of work to be done before the game moves past the alpha stage of development.

"It is a work in progress and therefore contains a variety of bugs...We strongly advise you not to buy and play the game at this stage unless you clearly understand what Early Access means and are interested in participating in the ongoing development cycle," Bohemia said in a statement, according to Gamespot.

DayZ is a unique entry in the zombie game genre as it allows players to forage for supplies in a massive open world and choose if they want to go solo through the game or team up with other players. The game began life as a mod for the PC game ARMA 2, and now the game has become an underground hit.