Insidious has a few admirable qualities and creepy visuals, but ultimately it's a hodgepodge of horror ideas with a plot that relies on a child in danger and a husband struggling to hold his family together.
The film opens with a ghastly Super 8 film of a family being hanged from a tree. Next we see Ellison Oswalt (Ethan Hawke) and family moving into the same house. Maybe we're not supposed to know it's the same house until a few minutes later when Oswalt looks out the back window at the (gasp!) hanging tree, but, come on.
So, Oswalt is in town to write about the murders and a missing girl. He moves his family into the murder house but fails to inform his wife of this fact. He finds a box of Super 8 film in the attic that shouldn't be there. The film cans have innocuous titles written in Sharpie: "Pool Party," "BBQ," etc. But they're actually snuff films of families being murdered, including the family that lived in the same house. Some of the families are murdered in annoyingly complicated ways. In one, family members are duct taped to patio furniture and pulled by ropes into the pool. Oswalt watches these in dark while chugging whisky. He has a moment where almost tells the police, but then decides against it. A serial killer is sneaking into his home and putting snuff films in his attic–what a scoop!
At this point some people might lose any sympathy for Oswalt. But I bought it, mostly due to Hawke's ability to make his character seem real despite hokey situations. Also this may explain why writers are such useful characters in horror movies. Writers tend to have more moral flexibility. The writer's creed is "Murder your darlings." When Oswalt decides not to inform the police of his find and risks his family's lives for the sake of a story, I said to myself, "He's a true writer!"
I'm reminded of John Gardner in On Becoming a Novelist when he told the story of coming upon an accident scene. He stopped to help a bleeding woman out a burning car. Despite the urgency he found himself grateful to be having such a rich and useful experience to add to his writing arsenal. Gardner wasn't proud or ashamed of this, he was just making an observation.
So the plot goes on. There's a ghoul in the films, and an occult symbol. And in all the murders a child was missing. A professor informs Oswalt that the symbol is for an ancient Mesopotamian god that was said to live in images and steal children. The original bogeyman. The film projector plays by itself, children in Halloween make-up start running around the house but Oswalt can't see them, he burns the film and projector but they come back, and eventually what you knew would happen happens.
The ancient god, Bagul, looks like this:
Sinister has something at the end that I hate, and I hope we've seen the last of it, along with strobe filters, Matrix-style fight scenes and slow-motion shots of guys jumping while shooting two pistols: it's the evil head-tilt. You know when the killer looks at the camera. He tilts his head in a gesture of sociopathic curiosity. Like, "Funny how this meat sack struggles so before I remove its intestines."