Finally saw this movie last night and I'm going to have to say, wow, I think the movie accomplished its objective, at least with me, based on the simple fact that almost 24 hours later I'm still contemplating it.
First off - my two complaints. The speaking was definitely too difficult to understand. Not because I couldn't comprehend the manner of speech, but because of the thick, thick accent of some of the characters combined with how "masked" vocals sound on TVs these days, expecially compared to sound effects which come blaring out 100 decibels louder (on a side note is that because of how sound is mixed in movies these days and simple sound systems of TVs can't keep up with it? Because I swear that is the case in nine out of ten movies I watch on TV via streaming, bluray, etc).
Second complaint is that this moving was advertised as horror and it's not. I would advertise it as suspense. Yes movies can, and the best ones do, span across multiple categories. But the overwhelming advertising of this was "Horror". But to me that invokes images of being scared. This movie was more unsettling. There's a difference between those two. I'm not blaming that on TCTTS or anybody else, simply on the fact that movies have to be categorized to be sold to the public, and often that means movies are set up for failure because they're sold as something they're not.
That being said there is a lot to digest about this movie after you see it in its entirety. Knowing what you do about Black Phillip by the end of the movie, it really throws prior scenes in the movie into a completely different light - the dialogue (what parts I could understand) about evil and sin; the twins singing about him; Black Phillip getting loose and the father wrestling Black Phillip back, temporarily. I think the movie's makers did a masterful job with setting the tone, using the atmosphere of the period to bring suspense, the imagery...everything.
Overall, one of the best "suspense" movies in a long time, IMO. And I think that's because the payoff wasn't a trick or surprise...it was exactly what the movie told you it was the whole time - pure, unsettling evil.