Everything starts off rather weird in this bit of horror excellence. The longer it progresses the more unsettling it gets. Before you know it things get terrifying. This is full blown stalker hell. All brought to life by two fantastic performances, excellent direction, and an incredibly disturbing plot that's full of mystery.  Best of all there's a noticeable sense of humor here and it doesn't manage to get in the way of the terror. The jump scares seem used just as much for comic relief as they are for scares. The movie does rely a little too much on them for the latter unfortunately. The real scares here come from the mystery and the wonderfully creepy performance from Mark Duplass.  It's a film that's great at making you wonder just what the heck is actually going on, as well as keeping you on the edge of your seat to see what will happen next. With a genuine sense of creepiness and originality, horror fans would be bereft to miss it.