I watched yesterday Rec 1, a masterpiece. This evening, Rec 2.
This is not an awful film after all, but several points below the first one (I voted the first 8/10).
Rec 1 transmitted to me a sense of confusion, mystery, it really makes you feel like you are one of the people trapped in that apartment, who doesn't really know well what is going on, both inside and outside the building. But the first film is realistic: deals about science, a virus, zombies (although they are faster and more intelligent then the standard), physical infection.
Rec 2 changes this to a demoniac possession which reminds the Exorcist. First film was science, second film is religion. I preferred science. In this second film Satan talks through the infected/possessed people, and like in The Exorcist is able to change the voice of its victim. I found that quite ridiculous, kind of a thing that would be never happened in 1st film, where the villains were infected and not possessed! So now why this stupid change?! It is just a bad mismatch if you pair it with the realistic horror masterpiece that was Rec 1.
Also, the characters were better in the first. They were just common people, their reactions were understandable, but why in the sequel a police team that should be quite prepared acts stupid more than once? They should know when to shoot, and react less hysterically even if the situation was tragic.
Even the camera was better in the first movie. You feel that the camera is really inside the movie, but here seems more "external". The cameraman never does anything except filming, like if in a situation were you are in a high risk of death your first thought is keep the camera in position. Then one of the policemen says, "how could we make the people outside believe what is happening here? Nobody is going to believe us!". Now, think about it, you took a member of your team that does nothing except filming all the time and you have no proof?! Bah.
So my final suggestion: watch Rec 1, that is very well made, realistic, full of suspense, does his horror movie job very well. Rec 2? Not so bad, but more than 1 stupid storyline decision that ruined this sequel, like the introduction of Satan and supernatural elements, and lack of characterization.