Frictional Games, developer of the Penumbra series, has announced the development of Unknown, an all-new survival horror game.

Set in the late 18th century the player will explore the eerie environments of an old castle. It's a journey through horrors and disturbing sights, built up during centuries of decay.

The game is in development using Frictional Games' HPL2 game engine, expanded to include tools for testing, creating and editing levels - all of which will be included as part of the final release, allowing for end-user content creation.

Unknown is in full production and is scheduled for an early Q2 2010 release. See the first footage right here.