The space-faring sandbox game Starbound hasn't even seen a full release yet through Steam, and yet recently it managed to hit quite an impressive milestone with some outstanding sales numbers on Steam.Developed by Team Chucklefish and released in an early form through Steam Early Access, the Starbound Twitter page tweeted out that the game has officially surpassed 1 million copies being sold via Steam. Earlier in 2013, the game was funded through an impressive Kickstarter backing of over $250,000 in just one day of its campaign being launched, with its beta being made available through Steam Early Access in early December 2013.The full version of Starbound is expected to be released later in 2014 for PC, Mac, and Linux, along with a later release on Vita.