From Darkness could have been worthwhile but as it stands, its just mediocre.
Perhaps its biggest shortcoming is its lack of true direction. Its story moves its focus in a way that robs it of tension and a clearly articulated, meaning. What remains isn't terribly engaging or even all that frightening.
Its a shame too, as the core premise has real scare potential. Moreover, its production values are reasonable, as are the performances, from the cast.
In summary, a horror film that could have been quite good had it had a simpler, more direct focus that built towards something worthwhile in terms of storytelling and associated scares. As it stands, From Darkness is not awful but its hardly memorable, either.