Today I watched Rec 3: Genesis, it was basically the first epidemic that started it all. In the first film we learn about a dog being infected and how the vet reported it which caused the building that the dog came from to be closed up. This movie shows what happened to the vet on a very special day.
It was basically the Romeo and Juliet of zombies. I enjoyed it, but the fact that people from the government know about this so quickly and act on it so fast is just unbelievable. It was a good movie and it made contributions to the past two films, it made us see how the priest in the second film came to be and then the dog and the vet situation was also seen in this film. I think what made this movie better was the way it was shot, the beginning is basically footage for the wedding video and after a few minutes it's actually shot cinematically no more "found footage".
The only problem with this series is the demon possession storyline. How is one demon in all of these people? We see the "demon" woman in question in the past two films, but we still don't know how this all works. We also see her in this film, possessing the people (in reflections). Hopefully it gets resolved in the next (and final) film.