Last month, Frictional Games re-released Amnesia: The Dark Descent as part of The Potato Sack - a collection of games available via Steam with some Portal 2 surprises packed in. The new adventure, Justine, was an unlockable in that version, and is now available to all.
Frictional Games is also offering a free soundtrack to those who pre-ordered the game or bought it directly through Frictional's
store
. It will be available for sale at regular price as well.