Amnesia: The Dark Descent could very well be the scariest game ever created. The game put Frictional in the spotlight both critically and by word of mouth. Many recent "scariest games of all time" lists rank it at the top or very nearby.
The next release, developed by The Chinese Room, was expected to launch near Halloween of last year. A trailer was released instead, the game pushed back a few months for extra polish to live up to the excitement. After nearly a year of silence, at least from its original launch window, the game is scheduled for release on September 10th.
Really, at this point, they could have waited until October although I am glad they did not.
Amnesia: A Machine For Pigs is not a sequel in terms of story. The story has multiple threads, some of which may be delusions. The protagonist, awaking from a serious disease, is haunted by a mysterious machine. If I understand correctly: a dark, supernatural, Victorian slaughterhouse on the day before the 20th century sounds like a great candidate for a survival horror game.
Amnesia: A Machine For Pigs will arrive September 10th, 2013. You are now able to pre-order, from many sources, for a 20% discount.