One upside to scoring big bucks off a cheaply acquired, shrewdly marketed, not-particularly-scary horror film: The marketing department can pretty much sit out No. 2.

So it is with Paranormal Activity 2 — of which little has been revealed besides the fact a tormented toddler and a nervous German Shepherd are now besieged by a dastardly demon’s dirty deeds.

No one wants to see loyal dogs or hapless tots bite it, so the addition of both proves as simple and cunning a hook as the first film’s: A couple chronicles its apartment’s haunting with catastrophic results.

Good horror movies demand attention. Last year, Paranormal Activity mistakenly catered to its deficit, lamely relying on Pavlovian cues to get people to stop tweeting, texting or talking and watch a Really Scary Thing That’s About to Happen.

Thankfully, more is mostly more in Paranormal Activity 2 — not much more in the end, but anything’s a step up.

Notably scary? Not really, but it boasts one terrifically terrible fright (one more than its forebear), more characters, less tedium and better acting, even in non-verbal roles. Plus, it largely discards wall-rattling bass that once preceded the demon’s arrival and plagued its predecessor’s pace. (Not entirely gone, it arrives late, and muted, enough so as not to rankle.)

Incongruously jumping from the John Irving-inspired drama of The Door in the Floor to haunted-house horror, director Tod Williams stages several scenes as dreadfully, discomfortingly still as those in Michael Haneke’s Caché.

Unaided by sound or sped-up time-codes during which we know nothing spooky will occur, Williams firmly affixes your eyes where they should be: Darting all over to anticipate from what corner of the screen something might twitch or leap. Williams rewards observance with WTF bits of barely perceptible motion. (Hanging pots and pans at one point feel as if they’re turning to stare.)

And, if not the found-footage conceit, at least its marketing ruse has been dropped. There are actual filmmakers and end credits this time, and fans of Jericho and late-period 24 will recognize Sprague Grayden as one of the first people onscreen.

She’s Kristi, a new mother to baby Hunter, whom we see her bringing home with husband Daniel (Brian Boland), teenaged stepdaughter Ali (Molly Ephraim), Spanish nanny Martine (Vivis) and dog Abby. All seems well in this well-to-do blended family until their home is ransacked, but nothing is stolen.

Daniel then mounts security cameras throughout the house — providing ominously omniscient views of the den, kitchen, foyer, stairwell and Hunter’s bedroom. For a while, they capture mostly benign haunts perpetrated on somewhat-bourgeois people. Then, in walks Kristi’s sister, Katie.

Yes, that Katie (Katie Featherston), last seen (by us) possessed and hovering over dead boyfriend Micah (Micah Sloat) before decamping to unknown whereabouts. Those unable to recall the first film’s timeframe (and, really, who would?) will cringe as Hunter is handed to her and she says Micah is “not up to hanging out.”

But later, in walks … Micah, most assuredly not a ghost. And there’s another reason Paramount isn’t showing much in trailers: Trouble with a capital “T,” which rhymes with “P,” and that stands for prequel.

Not for nothing is the 2, as sequel moments certainly apply, but as the demon’s visits again intensify into familiar levitation, dragging and biting attacks, Paranormal Activity 2 resorts to same shenanigans, different domicile. (Even Hunter becomes just a poltergeist’s prop, although not quite to the degree of immediate danger one trailer suggests.)

“The more we paid attention to it, the worse it got,” Katie reminds Kristi of their childhood run-in with the demon. The same could be said for how the filmmakers handle fleshing out those characters’ curse.

Yes, cultural snobbery amusingly backfires, and there’s an admirable climactic mean streak. But the last act clearly crams in mythology meant to give life support to sequel/prequel opportunities. (At one point, the 1930s are mentioned. Let me guess: Hand-cranked cameras for that one?)

Paranormal Activity 2 is reminiscent of Saw II — modestly building on a so-so introductory film to something slightly more accomplished. But anyone who sat through Saws 3-6 will attest to the fine line between incremental improvement and getting greedy.

This coda’s creaky bid for its own annual franchise status feels a lot like crap tossed in a candy bucket and called a “treat.” No one needs Paranormal Activity 7 in 2015, let alone Paranormal Activity 3 in 2011.