The thing they sell you on in the previews is the black phone in the basement that isn't hooked up yet nonetheless receives calls from a supernatural source. I generally don't enjoy Ethan Hawke, but that phone gimmick was a strong hook.
The movie starts out fairly strong. It's the 1970s, so for those of you of a certain age, there's some nostalgia value in just seeing the '70s brought to the screen.
They have a decent setup: kids disappearing, taken by the Grabber. The main character is an abused boy whose classmates have been going missing. They set up a little parallelism between the abuse of kids in general and the kid's father who beats the crap out of his kids. So there's a lot to mine for engagement: abusive family, tight bond with sister, sister's psychic powers, and a whodunit regarding the kidnappings. But the moviemakers fail to capitalize on any of it.
The problem with this movie is that once the kid is trapped in the serial killer dungeon, the moviemakers didn't know what to do with the movie. So they throw out some side content about the kid's psychic sister, but generally speaking the movie just wanders around until it kind of ends all of a sudden.
Yes, there is a cogent narrative thread, but there's no pacing, no suspense, very little of a climax, and no epilogue or denouement. So in terms of being emotionally effective, this movie is weak. The ending isn't particularly satisfying.
Ethan Hawke does a good job with what they give him, but they don't give him much. So we don't get a portrait of a sick mind or engaging weirdness.
My biggest complaint is that they don't do much with the supernatural angle. Other than a few mysterious phone calls, there is almost nothing. The direction is flat. The scariest moment for me was when the little sister is riding around and gets a stunning hint from the Grabber's victims that she's in front of the dungeon house.
As a writer, I could sense there was a drama behind getting the screenplay written. Something went very wrong in translating the original short story into a shooting script. Likewise, the direction was weak. So in the end, we get a thriller that isn't suspenseful or thrilling. Since the short story was written by Stephen King's son, I suspect that this project was a square peg that a whole lot of influence got crammed into a round hole. Without that name behind this movie, I don't think it would have been made.
I don't recommend you watch it, but if you must, I suspect that intoxicants will greatly improve your viewing.