Microsoft have today announced that the hit zombie game State of Decay has become the fastest selling title to ever hit the Xbox Live Arcade. Since it was released on June 5th to critical acclaim, State of Decay has been purchased more than 500,000 times.

Following this spectacular launch, developer Undead Labs have expressed gratitude towards all the fans who “bought the game and are having a great time playing it.” In order to increase enjoyment, the developers have already begun work on free DLC. The first title update launched a few days back, and Undead Labs is already finishing off a second content update that is intended to “delight State of Decay fans.”

Undead Labs have also said that they’re working on a Steam release for the game. State of Decay was always developed with a PC version in mind, so the bulk of the compatibility issues have already been fixed. The developer just needs to implement Steamworks support and flesh out the keyboard and mouse controls.

Undead Labs have also stated that once the PC version is out, they’ll be working on a sandbox mode for the game that is based more on pure survival.

Sate of Decay is currently available on XBLA for 1600 Microsoft Points.