Swedish developer Frictional Games this morning introduced Penumbra: Overture, previously released on Windows and Linux, and now available for Mac OS X.

Penumbra: Overture is a first person adventure game with game play very similar to the hugely successful Myst franchise, which arguably kick-started this game genre.

Game graphics are rendered in real-time with advanced physics, the developers say, promising an, "intriguing story with a dark and disturbing atmosphere."

The game focuses on the story and puzzles, rather than in-game violence, players need wits, not virtual muscle to progress. The advanced physics engine lets gamers interact with objects around them, opening draws and picking up objects using natural, gesture-based mouse movements.

The Windows version of the game won some critical acclaim as being one of the scariest game titles released last year. This Mac port is a Universal Binary that works happily on both Intel and PowerPC-based Macs.

The developers - who originally intended to release the title on all platforms at once - admit to meeting some unexpected challenges developing the Mac version, challenges which, now overcome, led the Swedish firm to promise: "In our future games we can commit to a continued support for all platforms."

A demo of Penumbra: Overture is available while the full game costs just $19.99.