Ugh.
I've played Slender myself, and it's... meh. Just meh. The first few jumpscares can be kinda scary, but it gets repetitive very quickly and the game just falls apart. Without the scare factor, the game is really boring and slow paced. Slender turns from scary to just annoying. They also did a bad job of putting together the story(atleast in the game I played), it's kinda like "Oh I'm here. Oh wait, now I'm here. Ah, now I'm over here? HOW DOES THESE PLACES CONNECT?!?!"
I don't recommend anyone to buy this game, because it's wayyyy overrated. If you're a Let's Player though and you want to get some views, this game is perfect for that since everyone 12 and below will think it's hilarious when you scream your lungs out for something that you really aren't afraid of.
TL;DR don't buy this game.
Oh, and don't you get me started on PewDiePie.