Perhaps not as many genuinely scary moments as the previews and reviews suggest, but the ones that are there are EXTREMELY effective.
You genuinely care for Katie and Micah, which makes the film work so well. Also, darkness has never been so creepy. Had to sleep with the TV on and wondering what I will do tonight.
Prepare for your back to be pressed against the seat from all the tension and creepiness. Sure, it builds slowly, but it WORKS well regardless and the film is all about mood and then BAM!
Poorly acted? Yea yea, whatever. Quit being so darn picky and enjoy the ride for what it is!