This is a great film. It's a spanish horror film which is kind of similar to Cloverfield and Blair Witch as it's filmed the same way. The story's about an reporter and her cameraman who are shadowing two firemen for the night, they get called to block of flats where and old women is trapped in her flat.
Basically it's a zombie film shot in the style of Cloverfield. I'm not a fan of modern horror films but this made me jump quite often. I'd definately recommend it. Here's a trailer.
It was remade basically shot for shot last year and that was called Quarantine but I've heard they changed the story and it sucks.