UNRELEASED GAME – ABANDONWARE
This game has not received new developments within the last few years and is unlikely to be finished in the near future, if ever. The copyright holder has displayed an inability or unwillingness to finish the game, or in some rare cases, may have given up their rights to the game entirely.
Slender is a first person horror game where your only goal is to find 8 manuscripts about the Slender Man, a paranormal creature.
The more directly you come in contact with the Slender Man, the faster your sanity drains.
Source: The Game Website.
>> Slender has been updated, but never officially released. Latest builds list versions 0.9x, but never fully finished.
>> Instead, the developer moved on to Slender: The Arrival
>> See also Wikipedia: Slender: The Eight Pages