We knew that State of Decay had a successful launch, but we just learned that they've had the fastest selling release for an original game on XBLA. Along with the news, Undead Labs also discussed upcoming plans, including their State of Decay PC release and a sandbox mode:

Record Sales: "Following an exciting E3 last week, we’ve been thrilled with fan response to a number of games that we unveiled. This morning, Microsoft Studios and Undead Labs shared some exciting news on the success of "State of Decay," an innovative zombie survival game offering a unique blend of open world action, strategy and roleplaying. In the week following its June 5 release, "State of Decay" has surpassed half a million paid downloads."

Second Title Update: "Seattle-based developer Undead Labs has been hard at work since the original release — with the first Title Update rolling out to fans around the world over the weekend. The studio is already putting the final touches on the second Title Update, which should delight "State of Decay" fans. Undead Labs interacts directly with the game’s fan community via Twitter and Facebook, as well as the official "State of Decay" forums at forums.undeadlabs.com, and the content of Title Updates is determined based directly on player feedback.

PC Version: "We're currently working on a PC version for release on Steam. Fortunately it's been in development alongside the Xbox 360 version since Day 1, so we just need to integrate with the Steam platform and add native support for keyboard and mouse control. We'll also continue to issue Title Updates at a fast pace to refine game balance and fix bugs."

Sandbox Mode: "Beyond that, we're laying plans for the future of "State of Decay" right now. There's an incredibly sophisticated simulation engine driving the world of "State of Decay" — we call it FateEngine — and it gives us 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. Beyond that, all I can say is we pay very close attention to what fans of the game are asking for, and their needs will largely guide our development priorities, so stay tuned."

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For those who are unfamiliar with State of Decay we've included game information and the most recent trailer below. You can learn more at: http://undeadlabs.com/about-state-of-decay/

"The end is here. Life as you know it has gone to hell after the mother of all zombie outbreaks. Now you and the few scattered survivors must band together to survive and rebuild in a 3rd-person action game set in a dynamic open world. You choose where to make your stand, designing and fortifying your home base, performing daring raids for food and ammunition, and rescuing other playable survivors with unique talents. The open, sandbox world develops in real-time, dynamically generating content based on your choices and the ever-increasing zombie threat."