There is one thing that I can say in praise of >Dumb and Dumber To, so I might as well lead off with it. It has a certain casual, easy comfort to its style. That is to say, it's a film that picks up the baton of mid-to-late-'90s comedy filmmaking quite effortless and without strain: this is true of the acting as well. Yes, the script is forced to acknowledge that 20 years have gone by since the original Dumb and Dumber, and those years have worn hard enough on co-stars Jim Carrey and Jeff Daniels that it's kind of uncomfortable to look at them goofing around like big kids. But in general, it has the texture, pacing, and energy of a film that might have come out around 1996 or '97. Y'know, right around the time that a Dumb and Dumber sequel would have felt appropriate and natural, and not like a desperate bid for relevance by a whole bunch of people whose careers have been out of gas for years and years - I mean, hell, when was the last film made by brothers Bobby & Peter Farrelly that actually made any kind of real impact?

So yes, as a piece of '90s nostalgia, Dumb and Dumber To - which is the best possible title for it, if I'm going to keep hunting for nice things to say - at least understands and appreciates the '90s, and recycles them effectively. Which is something, I guess, but it would be much, much more if the film's archaeological precision was in service to something with more meat on its bones than this pathetic re-tread, which somehow took six credited writers to cobble together, despite fully half of the content being re-dressed or outright re-used jokes from the original film. The plot, once again, is a travelogue: best friends and dysfunctional idiots Lloyd Christmas (Carrey) and Harry Dunne (Daniels) are back in action after 20 years, during which time Lloyd has been faking a catatonic state as a prank against his buddy. Harry's kidneys are about to fail him, and he's discovered that a fling 22 years ago with the legendarily promiscuous Fraida Felcher (played in the present by Kathleen Turner, whose admirable openness about taking this role for pragmatic reasons does not make it any more pleasant to watch such an iconic star make her big comeback as the butt of such mean-spirited jokes as the film blandly lobs her way) led to a daughter. Hoping that she'll donate an organ, the man-boys truck out to find where she ended up after Fraida put her up for adoption, only to end up on the wrong side of a conniving stepmother (Laurie Holden) and handyman (Rob Riggle), hoping to kill the girl's adoptive father (Steve Tom) for his millions and his world-changing new invention. It then takes another road trip out to El Paso, to crash a weak-kneed parody of a TED conference where the daughter, Penny (Rachel Melvin) is accepting an award on her father's behalf. And along the way, Harry and Lloyd are virtually always dumb, when they are not dumber.

It's impressive, after so many years since his heyday, to find that Carrey (51 at the time of shooting) still has the ability to wheel his head around like a whirligig, and flex seemingly every single one of his facial muscles in a different direction all at once (though I must confess to never having found that shtick funny when it was new, and I'm surely no more inclined to it now). And he and Daniels fall instantly into the most relaxed, natural rhythm of feeding off of each other, reacting and leading, stretching moments until they're about to break, and playing the duo's bits and routines with the timing of ballroom dancing and table tennis combined. But mechanically impressive comic acting is all for naught if there's no comedy to back it up, and Dumb and Dumber To is a skeletal wasteland of uninspired, witless non-humor. The Farrelly's humor hasn't felt boldly trashy or dangerous in many, many years, and the calculated packaging of outrageous behavior is the exact antithesis of the sneering, anarchic obnoxious that made them the most successfully edgy mainstream comic filmmakers of the '90s. Dumb and Dumber To is everything and anything but outrageous. It tries, but the same old gross-out sex jokes and low-key bodily fluid humor feels ossified and underwhelming now. Even as someone who never found Dumb and Dumber worth much of anything, I can recognise that film's brazenness; its sequel is a calculated marketing effort, and that shows through every belabored gag set-up and lazy one-note joke bloated out beyond its appropriate limitations.

I don't know that it's surprising that this is where '90s nostalgia leads us: the flailing, overly self-aware pop culture of that period was hardly interesting the first time, with its desire to make everything extreme and loud clashing with the era's unusual facility with recycling. Trying to revisit Dumb and Dumber is self-defeating: one generation's brash newcomer is the next generation's quaint old-fashioned piffle. And this is precisely the pit into which Dumb and Dumber To falls: it combines boringly obvious jokes and plot developments with a misguided hope that bratty attitude and yelling will somehow give it all a sharp comic edge, and this bond doesn't hold even a little bit. It's easy to imagine far worse belated sequels than this, but in terms of being pointless and pathetic and obvious in its elevation of mercenary over artistic concerns, it's hard to name a recent sequel that has been more thoroughly unwanted, unneeded, and disposable.