Ever since its release on Xbox 360 and PC earlier this summer, Undead Labs' action-packed State of Decay has been the go-to game for slaying the undead and enjoying hard-hitting action.

The publisher announced this past week that it has sold more than one million units of the game across both platforms, making it a bonafide success. The team isn't done yet, either – it's looking to expand the world sooner rather than later.

A new downloadable content pack called Breakdown is in the works, and currently sits in Microsoft's certification process. If all goes according to plan, it'll find its way to both Xbox Live and PC later this month – with more to follow in the months ahead.  

State of Decay is available now for Xbox Live Arcade and PC.