Some of the worst filmmaking I've ever seen. These flaws aren't nearly as intentional as some would have you believe. The movie frequently violates its own rules by having the killer move in front of the moving camera that he's meant to be holding, or playing sound effects over the found footage. The acting isn't as bad as everyone says either though. Ultimately it's a poorly researched and executed movie. 2 stars.
This shouldn't work on so many levels - almost uniformly horrible acting, a few laughably cheesy moments - but it does. The post-processing on the tapes (static, noise, roll, color deformation) is almost the star in itself, and helps to create some of the most unique and genuinely creepy atmosphere in anything I've seen. I hate the "horror" genre, categorically, but this is a hugely underappreciated gem.