Quite possibly the best flash game I've played.
The first game, though a decent puzzle game, had several fatal flaws which prevented me from really enjoying it. This sequel, however, is incredible. The author is serious when he says to turn off the lights and turn up the sound. I absolutely love the atmosphere of the game, reminiscent of the good old zombie movies before the crappy Dawn of the Dead.
Three or four times throughout the game I actually jumped a little, even when I was expecting something to startle me. The sense of urgency throughout it adds so much to the experience, though the Sudoku puzzle hurts that aspect a little.
All in all, one of, if not THE, best flash games I've ever played, and easily the scariest game period.