Okay, here goes. Right off the bat I have to say that the actors and actresses give this movie their all. There is nothing more that they could have done.
It's almost everything else that needs some work. Here is the best advice I can give you: don't watch the trailer. I MEAN it. It will be a big temptation. I eventually gave in before watching the movie. The trailer gives away almost every single scare. I never jumped once throughout the entire film because I was able to predict it all. The movie is the least scary of all three, but it is also the most emotional one.
From here on out it's spoiler-territory. You have been warned. This third chapter had so much going for it. As I before mentioned, the cast is perfect. An idea of a prequel instead of a sequel has promise. The main villain is genuinely creepy. All of the thematic ideas are in the right ball park. But notice two key words I just used in the past couple sentences: "main" and "ideas". This film has too many enemies for the characters to face. In a way, it's kind of like what people have criticized The Amazing Spider-Man 2 and Spider-Man 3 for. The amount of villains dilutes the threat they individually pose, as each one has to have its own narrative thread, expelling any tension that builds up. What's really bad is that this is a short horror film. All the little breaks in the plot after the opening scenes change the pace considerably for the worse, which dispels the terror one should be feeling.
I can understand the writers trying to tie this prequel into the other films, but to do it effectively they needed to expand the length and not repeat some of the same scenes, like the ones where the veiled woman lunges for Elise's throat, over and over again. There's so many ideas, but they're only hinted at. I, for instance, wanted to know more about the history of the guy with the breathing mask. All we are given is that he used to live in the apartment complex.
While what the other-worldly things say can be greatly menacing, some of the other lines of dialogue said by the characters can be corny, discordant, and incomplete. You can tell the actors can feel it too. The words they should be saying are on the tips of their tongues, but they're holding them back. Those words they don't issue out are powerful. In the scene where Elise talks about her husband's suicide she abruptly stops when she is about to talk about how his one major action affected her feelings about herself. What the writers don't let her say is that she feels like she's the one responsible for his death. THAT is why she needs to find him in the afterlife: to convince herself that she didn't unwittingly kill the man she loved.
Yes, Elise finally gets to show some hutzpah. But what she showcases with that strength is how weak the villains really are. All she needs to do is keep pushing them away from her, with the demons, as a result, flying through the air and needing to catch their imaginary breath. Oh, that's right. Breath. The man with the oxygen mask has a big weakness. I think I just gave it away. Sorry. It's just to prove a point. How can that man fly all the huge items in a room around in a big frenzy and knock people down telepathically and be able to teleport himself between the apartment floors and still be able to be so easily defeated by an old woman who could beat him in 10 seconds flat with just her hands as weapons? He really has no displayed effective offense. The man just keeps shrinking away because he's not strong enough.
Right when I felt like the tension was finally starting to build, the demonic issues were resolved. Almost all the other problems regarding everybody but Elise, Specs, and Tucker are never addressed. For instance, Quinn wasn't supposed to walk because her legs were crushed by a car and needed a great deal of time to heal. When the demon possesses her he makes her use those legs, and the legs are observed starting to snap. After the demon is gone nobody talks about how the girl's legs are probably now destroyed permanently from the extreme exertion the man used them for. The film closed. And the reference cliff-hanger ending was given away in the trailer also.
This is one of the biggest film disappointments I have ever had. There is a genuinely great horror/intense emotional drama film this movie lays the framework for. Sadly, the gaps are only hinted at and never filled. The characters, their portrayers, and the plot deserved much more than what the writers and the director had, or were willing, to offer.