The results are not good..
THE MONEY QUOTE
Slender Man took a blank slate of possibilities and turned it into a tired retread. It’s a strange choice made even more curious considering the popularity of the creepypasta seems to have waned in the last few years. There’s a chance that Slender Man will work for a group of teen girls during a sleepover, but for everyone else, it’ll be a maddening experience in tedium. There’s some imagery from earlier trailers missing in the final cut, making me wonder what White might have originally envisioned, but even then I don’t know that anything could’ve saved this.