Since there is an ever-growing number of these types of films, I'm going to have to come up with a name for them...and that name will be "meta-haunting". A meta-haunting is a horror movie that follows the traditional haunting format, but adds in a twist in an effort to escape the tropes of the conventional haunting film. This doesn't mean that all meta-haunting films are creative, nor does it mean it is impossible to make a conventional haunting film effectively today (We are Still Here is an excellent example).
The Diabolical is one such horror movie that fits the meta-haunting mold, for as it turns out, there is more to the haunting than is initially speculated.
Sadly, with this film it is difficult to dive into the intricacies of the story without giving up much of the plot, so if you'd like to experience the film with an open mind, proceed no further.
The twist in this film resides in the manner in which the haunting is taking place. It doesn't take long, with various clues strewn throughout the film, to realize that the haunting isn't supernatural at all. Our ghost's "phasing" in and out of the earthly realm appears like an electrical disturbance at times, seemingly affecting time, space, and gravity in a sporadic manner. Our protagonist, played by the scream-queen-esque Ali Larter, discovers that there are experiments being performed by a company called CamSET which may be causing the haunt-like disturbances.
Without giving away any more, in case your attention has been grabbed further and now you want to see it without going to third base, the film continues down this path of a time-based haunting of scientific ramifications.
The special effects were mostly commendable, with many of the "apparitions" spawning in a Silent Hill-like state. These squirming and writhing corpses were more effective than I was expecting based on my initial budget diagnosis, and were a welcomed surprise amidst the intriguing visual cues involving time and space. Ali Larter and the rest of the cast are believable and refrain from detracting from the story.
If I issued one complaint, it would be the constant slow-motion cues throughout. I've never been a big fan of slow motion in any film. Only rarely is it a necessity to supply visual aid or otherwise emphasize danger, but in almost all cases it doesn't instill any additional dread. This film does take opportunities in slow motion to show off its practical effects work, which isn't too shabby at all, but it is otherwise annoying at best.
The completion of the twist, particularly in the resolution of the film, is left wanting. I found myself confused and could have used a little more explanation on the happenings of the characters. It isn't that the concept didn't make sense, but the ending put into question the motivations of the apparition, and basically the motivations of everyone not in the home. While the way the film is devised didn't leave room for much clarity, it would've been nice had the writer found to way to work in a little more information.