State of Decay has surpassed 500 thousand copies sold and downloaded on the Xbox Live Arcade store, according to Microsoft.
The official Xbox blog specifies that State of Decay is the "fastest selling original game ever" on Xbox Live Arcade.
According to Undead Labs founder Jeff Strain, there is a future for the series. "We're laying plans for the future of State of Decay right now," he said.
"There's an incredibly sophisticated simulation engine driving the world of State of Decay - we call it FateEngine - and it gives s a platform to do much more with the game. For a start, I can tell you we're working on a sandbox mode designed to be a pure survival simulation."
Strain also said the studio is still working on the PC edition of the game, which costs 1600 points on the Xbox Marketplace.
A patch for State of Decay intended to fix several launch bugs was proven faulty earlier this week, but the studio is currently working on another fix.
An Australian release for State of Decay is due shortly, following a delay.