CONTAINS SPOILERS. LIKE THAT'S A BAD THING.
It's our fault. We get the comedy we deserve and if this is what we're prepared to pay for and support, this is all they're going to bother making. You've got to do some serious work to make a Scary Movie that's actually worse than any of the others in the series, but they've done it. You've got to struggle mightily to produce a film that's not only less funny than Scary Movie 4, Scary Movie 3 and indeed most of Scary Movie 2, but is also substantially less funny than the straight horror movies it thinks it's spoofing - but they've done it. In this instance the choices are the obvious Paranormal Activity series, the perhaps less obvious Mama, Black Swan (which was three years ago, so no marks for topicality), Inception (also three years ago), Rise Of The Planet Of The Apes (two years ago) and the Evil Dead remake which is at least this year's. Throw in some poo gags, Charlie Sheen riffing on himself as a perverted douchebag, someone pretending to be Tyler Perry in drag as Medea (a reference which means bugger all outside of the USA and probably not much within), Snoop Dogg as a stoner....voila, you've got a film.
Scary Movie V (it's written as Scary MoVie on the poster and the title card, but that just looks stupid) basically does the usual spoof movie routine of knitting together half a dozen fairly recent releases ripe for parodying. This ramshackle sort-of plot is nothing but a clothes line on which to hang sight gags, celebrity impressions, references to other movies, and a string of theoretically hilarious fart, bum, poo and sex jokes that don't make any sense in the narrative (any more than they did in, say, Airplane! or the Naked Gun trilogy) but somewhere along the way, in the decades they've been doing spoofs, parodies and pastiches, the humour has been lost.
It's not the gags are so abstruse and philosophical that you won't catch them. You do catch them, easily, but you don't actually laugh: at no point was I even close to a smirk. I honestly don't believe it's me and my tin-plated sense of humour, even if it went AWOL at some point during the Major Government. I do sometimes laugh at other things. But not here. You don't even have the majestic Leslie Nielsen any more, turning the lamest material into something approaching tolerable with a decent sense of timing for the one-liner or facial expression. In fact, you don't have anything but a bad idea desperately in need of putting out of its, and our, misery. Bet it won't happen. As long as these things keep making their money back, they'll continue to churn them out. Oh joy.