Could be scarier.

First of all, I believe that the Slenderman model doesnt look very scary, and when he kills you the effect isnt very exciting.
When you look around you tilt at an angle a bit, but this may have been intentional.
The controls are fine (aside from the buttons being a tad unresponsive). I wish that you could map the buttons to different places.
Im very happy that you made this app free for a limited time. As it stands I dont feel comfortable paying for this, but I hope that changes.

Mdnfalls about X-Slender, v1.2