Open-world zombie survival game DayZ, which is still in an unfinished state, has now sold more than 875,000 copies since its initial launch on December 16. Developer Bohemia Interactive announced the news on the game's website last night.

　　The game sold 88,000 copies in 12 hours, 172,500 copies in 24 hours, and 400,000 units during its first week. The standalone DayZ alpha sells for around $30, meaning it has now generated many millions of dollars for Bohemia Interactive.

　　The developer also has announced that it does not expect that DayZ will reach beta status before the end of 2014.

　　Overall, Bohemia Interactive said it was surprised that the game has seen such an overwhelming response from fans, mostly because the game is simply not finished.

　　"We didn’t want to compromise on the brutal and unforgiving nature of the early days of the DayZ mod so we’re very surprised to see such interest as this clearly is not a game for everyone, especially considering that there are some radical changes under the hood in comparison to the mod," CEO Marek Spanel said.

　　"In the short-term, we’re going to focus on the most critical problems you’re experiencing [at the moment] and at the same time we’re going to work on the road to the DayZ Beta," he added.

　　Spanel also released a list of the existing top priorities that Bohemia is focusing on to help improve the DayZ experience overall. These are listed below.

　　Server performance, stability and securityAnimals & huntingCooking & gathering resourcesPlayable user customizable vehiclesPlayer created constructions in the environmentMore complex interactions with the environment and crafting optionsStreamlined user actions and interfaceControl and animations expanded and improved for fluidityUpgraded graphics and physics engine (including ragdoll, etc.)Support of user mods and more flexibility for user hosted servers and game types