Stars: 1.5/5
“You Should Have Left” does not afford the viewer the courtesy of a proper introduction, so I plan to follow suit in critique of it.
The film struggled to maintain its two dramatically differing conflicts, oddly prioritizing the mundane marital issues of Theo Conroy (Kevin Bacon) and Susanna (Amanda Seyfried) over the vague yet obviously sinister nature of their seemingly quiet getaway home. The true stakes of most situations were painfully ambiguous as any plot-related scene could (and often would) end with a main character jerking awake from a nightmare.
In fact, the first scene(s) boldly followed this formula and turned out to be Theo’s nightmare about his daughter Ella having a nightmare, both of whom wake when a man eventually identifiable as Stetler assaults Ella, first in her own nightmare then in Theo’s. 
Horror is a generous tag for the film, whose few onscreen “paranormal” threats include a man in a baseball cap and a candid photographer with a Polaroid camera and no boundaries.
Musically suspense-building scenes mostly just follow Theo wandering through the house looking for lights like a moth and turning them off. Its horror element seems almost an independent problem only meant to distract from the real, less pressing conflict of the story: Theo and Susanna’s rapidly deteriorating marriage.
It would be much more digestible to separately explore the nature of the seemingly haunted/cursed house and the hardly notable, perfectly believable relationship troubles of a man (preferably still Kevin Bacon) in Theo Conroy’s position. There is surprising complexity to Theo’s past as the subject of a highly publicized court case in a suspected spousal killing before the splendid and noticeably younger Susanna came into the picture.
Most of Kevin Bacon’s dialogue is clunky and awkward like it’s a poorly translated dub, but watching those sweet slender lips while he talks confirms that he’s actively speaking that garbage. While I strongly advocate for and praise Kevin Bacon, I equally resent him for giving me hope for the movie with his presence only to be violently let down.
It is, of course, more difficult keeping a degree (or six, in Mr. Bacon’s case) of separation between Bacon and his character when he had a hand not only in acting but in production. In the brief sliver of time toward the end where his character stands for any ideal, he doesn’t communicate his good intentions effectively in the least.
On a technicality, I cannot in good faith spoil one or more of the “twists” in order to continue ragging on the plot as I would like. I will say, however, I preserve those nuggets of surprise not with respect for their narrative purpose. It’s more like laying landmines in a ninety minute window that make you cringe when stumbled upon.