I usually have little problem accepting genre conventions. Without being a big fan of exorcism or daemon’s hunting films, I believe that I understand the rules of the genre. Something odd (and bad) happens however with The Conjuring. It takes the genre seriously.
Director James Wan has the original Saw in his directing record, and he was the executive producer of the next six films in the series. He should know something about genre rules. One golden rule is that you either need to abstract the details to give the story a more generic touch (this is what was done with Saw which could be seen as a pure horror exercise, enhanced by the claustrophobic and time bomb effects), or include a touch of humor or some other elements to allow detachment of viewers from the ‘tough’ stuff. The damaging mistake made in my opinion in The Conjuring is that not only that none of these two elements is present, but also that all the story is taken so much in serious up to the claiming that it is inspired by true events and characters. What if you are not a Roman-Catholic, if you do not believe in daemons, if you doubt (as many Internet sources do) that Ed and Lorraine Warren (the couple of demon fighters in the movie) were really anything else than story tellers at best, fraud at worst? This film does not let you room to enjoy, because if you do not accept the convention little makes sense – story, dialogues, characters.
There is some good horror cinema in this film, which tried and to some extent succeeded to paint the action in a retro early 70s atmosphere, using film means of that period. However, the weak premises of the story make everything look artificial, and when noises become more strident and bodies start being dragged faster or fly higher, the lack of credibility is so strong, that it the even more ridiculous solution comes as some kind of relief.