The Real Texas is an upcoming adventure game which will be available for Linux, Mac and Windows. The game looks quite interesting with some features that makes it different though it is an old school top down adventure at heart. (videos below)
Sam, and ordinary Texas rancher, is on holiday in England when he falls into a blue portal and lands in The Strange Texas which is really just a sort-of satire of his own real world.
The gameplay is similar on the lines of The Legend of Zelda: A Link to the Past and Ultima VI with some interesting twists. There are no swords in the games. The hero uses a gun and the controls are similar to FPS games where you move the hero with keyboard and shoot/aim through mouse.