There is a way this ending could have been executed without relinquishing its grasp on both the mundane and the horrific, and I would have loved that success. But it doesn't detract from the disturbing set-up that's equal parts Southern Gothic and X-Files episode, a tautly conceived fable that has the structure of stories I loved as a kid with implications far more distressing.
2-3. Manages decent production quality (Bill Paxton does a fine job directing) and nuanced characterization. However, one of the film's several eleventh hour twists essentially destroys what the film's characters had appeared to be up to that point, leaving it thematically empty. I also wouldn't call it an especially subtle film; just clear and (mostly) competent at a base level. I probably wouldn't watch it again.
This film assumes the worst about God's character, and in doing so comments on the upper limits of faith -- eventually asking if the lack de facto makes one a sinner, or worse: inherently evil. And it explores this heady theme with some beautifully horrific sequences, superlative child acting, and a complex performance by Paxton. Not for everyone, but I think it's a gem of a film