Runic Games' Diablo-inspired action role-playing game Torchlight has sold 500,000 units, just weeks before its May 12 arrival on Mac via Steam. Torchlight hit the sales milestone a little over six months after the title's original PC download release on October 27, 2009. The game is the first title from Seattle, WA-based Runic Games, which was founded in 2008 by staff from the teams behind Diablo, Diablo II, Diablo II: Lord of Destruction, Fate, Hellgate: London and Mythos. Aside from digital storefronts, Torchlight also released to physical retail in January this year in the U.S. in a distribution partnership with Encore, and in March in Europe as part of a deal with JoWood Entertainment. Perfect World announced a publishing agreement with Runic Games for Torchlight in August 2009. The action RPG Torchlight is just the beginning for Runic, as the studio is currently working on a free-to-play Torchlight MMO. The game normally retails for $20, although in conjunction with the sales milestone and the game's release on Valve Software's newly-available Steam for Mac distribution platform, Torchlight is currently selling for half off on Steam. "We are delighted by the response to Torchlight," said Runic CEO Max Schaefer in a statement. "We’d like to thank the greatest gaming community in the world, Valve, Perfect World, World Domination (Mac port), and all our other distribution partners for making this possible."