I can appreciate this movie from many standpoints. Although I do believe that the Slender Man thing has been WAAAAAAY overdone in recent days to the point where I'm starting to dislike the people who like Slender Man, I actually do like some of the really good content made from the "legend" of Slender Man. Now, if you don't know the Slender Man phenomenon started back in 2009 or so with some photoshops of images created the iconic Slender Man on the Something Awful forum, specifically this thread. Others eventually came along, like MarbleHornets (that's their YouTube username) and started creating some videos based off of the newly created folklore of Slender Man.
This movie is all kinds of things. It's definitely riding off of the success of MarbleHornets... and the problem is that it's kind of hard not to be doing so. Both the video series and this movie have a group of people filming a movie as the characters start losing it and seeing Slender Man. Now, while I really like MarbleHornets, the premise of that webseries has become muddled and confusing to me for a while. Yes, I enjoy the content, but I long ago gave up trying to figure out what was going on. Windigo, on the other hand, is very straightforward. The plot is easy to follow, everything is setup well, and the content flows nicely. The movie could easily be divided into two parts: the beginning and setup of the characters and the story, and the ending which is a bit of a confusing cluster of images. While I did enjoy the setup, even if it moved slowly, the payoff was both satisfying and a bit annoying.
My least favorite part of the movie was the film tearing and the screwing with the contrasts and saturation levels and everything else. It took me out of the film knowing that these editing techniques can be done so easily. This is one of the reasons I like MarbleHornets... most of the time they have a much subtler way of showing the distortion, whereas this was really over-the-top, something I simply didn't enjoy. It definitely tries to keep the tension raised, but the stakes are never all that high, and even when they are the "special effects" and the copious amounts of quick deaths I couldn't make out just made the whole ending of the movie incredibly overblown. The saturation levels change constantly through as well causing more distraction than terror in the second half of the movie. The subtler "terror" worked pretty well, but the ending with the random shootout that looked more awkward than good and Slender Man on fire just seemed silly.
I don't really have much more to say about this one. It's exactly what one would expect from a movie about Slender Man. The beginning is pretty slow, but there is a build up there. If you've watched any of MarbleHornets, you know basically everything that's going to happen. The one big difference is that the town is against the filmmakers... for... uh... some reason? It's ever really explained and I didn't really get that at all. I guess they were hiding Slender Man's presence... for reasons? I don't even know. I think there was a zombie thing at one point too... not sure why at all. Because you're basically getting exactly what you expect, it's no better and no worse than what you're going to expect. It's ultra low-budget, but does have some decent actors as well as some that aren't so great. The scenes are pretty good on the whole though... and when distortions aren't present the movie actually looks pretty good. Slender Man doesn't really look all that scary... more like a dude in a suit, but parts of the film use him effectively, especially when it uses him more as a psychological issue than a real one.
I would only recommend this to hardcore Slender Man fans. While it's not a bad film, it's not really made for somebody who doesn't know anything about Slender Man or somebody who doesn't have some pre-existing likes for him. I'm pretty lukewarm on the movie as a whole, but there are some effective scenes, particularly the final one. Check it out if you're interested.