Spiderweb Software has announced the release of Avernum: Escape from the Pit, a new version of their classic turn-based fantasy role-playing game for the Mac. (Windows and iPad versions are coming in 2012). A free demo is available; it costs $20.

In Avernum, you’re banished to a subterranean kingdom after raising the ire of the emperor. You lead a struggle in this prison underworld to return to the surface. The game features hundreds of quests, hundreds of magic artifacts and a huge game world to explore. You can complete three game-winning quests as you master more than 50 spells and battle disciplines.

This isn’t Avernum’s first release; it’s the latest evolution of a game that’s been around for a number of years. Spiderweb Software says that the remastered Avernum: Escape from the Pit contains overhauls to the gameplay system, graphics, compatibility and interface. If you do own the original Avernum or Exile: Escape from the Pit, you can get a $10 discount on this version.