Over the course of the movie, various of the residents are bitten and infected or torn apart by ravenous zombies. Then the other characters are killed off and finally it's all down to the girl and her camera man. Turns out someone was running experiments in the attic, which became infection ground zero when the subject escaped.
I watched the original Spanish version a couple of years ago and loved it. Naturally, if you dislike first-person movies you shouldn't bother to begin with, otherwise I'm confident horror and zombie fans will agree with me. The characters were interesting enough but more importantly the action and suspense carried this flick all the way through. Doing a first-person movie is like doing a first-person novel, rather than being used as a cheap gimmick, the style must suit the story and not be shoehorned in. The things you can do with first-person - such as only show what the person could see - must be used to further the story and add to the tension or doubt. Since we can't always see what's happening and we only know what the protagonist knows it sometimes forces us to use our imagination and thus fill in the gaps. Plenty happens off-camera in REC, with lots more being shown in flashes or glimpses, adding to the value of re-watching later. As a matter of fact, I feel like watching it right now.
The remade American version is pretty much the same as the original, except in English and with a different cast. For some reason it's also not as good. I can't put my finger on it and perhaps it's simply because the American lead actress wasn't as good as the Spanish one, or maybe because I'd already seen REC and the remake was literally a carbon copy. I should probably mention at this point that the American remake is called Quarantine, not REC.
The only person really worth mentioning both movies is the lead actress. In REC it's Manuela Velasco, for Quarantine we get Jennifer Carpenter (of Dexter fame). Manuela is a good-looking woman...
Jennifer Carpenter reminds me of a man, but perhaps that just a residual memory from watching Dexter when it was still worth watching.
Anyway, that's just my opinion.
REC the original gets 8/10 from me, the remake maybe 6.5/10. Sorry, no nudity today. There was none in the movie and neither actress appears to do nude scenes. Two thumbs up for them, I guess.