Basically, the whole Slenderman meme is just a rephrase (or simply plagiarism) of the great Stephen King shorty called The Man In The Black Suit issued at 1994. Here's a link to the Wiki page where anyone can read the plot summary
http://en.wikipedia.org/wiki/The_Man_in_the_Black_Suit Anyhow, that "man in the black suit" is nearly the same as that Slenderman. The only difference is that King's tall-man is a lot more frightening, because he is usual, normal, just an unusually tall man... who prefers to eat children. And if I'd be doin' Slenderman theme game I'd doin' it somehow similar to Stephen King's that short story. There's just a forest and a tall-man, who is very hungry and wants to eat you. No f**king pages, no f**king darkness, no scary sounds, everything as calm and normal as could be. Shiny day, gorgeous forest, river full of fish, birds are singing, wind is fingering the leaves, etc. Even the tall-man is normal, just too tall. And it's too late when you realize that the tall-man you just met wants to eat you alive. And the only thing you can do is run and hide, mostly run as hell. Short and effective. I presume.
If there's anyone who have read Stephen Kings "The Man in the Black Suit" than that's somehing that is interesting to discuss. I mean "The Man in the Black Suit" vs. "Slender the Arrival" or just Slenderman poppy-sloppy meme.