Sales of 250,000 in its first two days have seen zombie romp State of Decay become the second fastest selling Xbox Live Arcade title ever.
The only game to better its performance is Mojang’s Minecraft.
"This was you,” a statement from developer Undead Labs said. “We did not have an ad budget. We didn't have a physical copy to load onto shelves, no worldwide multimedia push, no studio reputation with millions of followers.
"All we had was what we believed was a great game and a great community. And make no mistake, a solid game is not enough, not in 2013. Plenty of great games wither away in obscurity. This train got rolling because you got out and pushed. We are not just riding on this train, however! We're never going to stop pushing to make the best games we can."
The studio has submitted a patch for the game to Microsoft that addresses a range of issues. It has also said that a PC version is in the pipeline, though it will likely not be released for a while to come.