Slender's a free game that scared the pants off of a lot of people. It was simplistic in the fact you had to find eight pages in a wooded environment while trying to keep a step ahead of Slenderman, who some say only want $20. It used the Unity engine and while the game was rather short, a lot of folks loved the atmosphere it created and loved being chased by the slender fellow.
A sequel is in the works and here's your first look at Slender: The Arrival. You can see the graphics have been much improved and it looks like you have to deal with more than just Slenderman as well as being in multiple types of environments. Due out sometime next year, Slender: The Arrival's sure to scare the pants off of more folks playing in the dark with headphones on.