Bad heads: "The Hangover Part II"

I didn't really get 2009's The Hangover, which seemed to me an especially crass, patchy, sub-Apatovian lads-behaving-badly tale, but plenty of other people did, such as to make a sequel an inevitability. On reflection, it had the kind of mildly ingenious pitch (Memento with boobs) that might have best remained an untoppable one-off, but then the film's essential conceit - and a large part of my problem - was that these guys weren't ever going to learn from their mistakes, and were thus likely to make the same mistakes all over again. And besides, money talks. The Hangover Part II, again directed by Todd Phillips, follows in the footsteps of countless 70s British sitcoms before it by relocating a familiar set-up to a balmier climate - in this instance, Thailand. Before you ask, yes, there are ladyboys. That's the level of comic imagination the sequel operates at.

A twenty minute drink on a Bangkok beach turns into another wild night on the tiles, and the heroes emerge from their stupors once again. Alan (Zach Galifianakis) has sacrificed his hair in the night, but gained a monkey; Stu (Ed Helms), the uptight dentist who lost a tooth first time round, has gained a prominent facial tattoo, but lost his bride-to-be's 16-year-old brother; nothing short of a full-scale nuclear assault seems likely to wipe the smirk from the face of Bradley Cooper's Phil, but that's just how this franchise rolls. Crucially - as the alarmingly mirthless opening half-hour makes apparent - the franchise has lost even those crotch-level gags audiences went for first time around, replaced by what now seems like an awful lot of plot for these characters to have to plod through.

If there's anything like an aesthetic at play in the Hangover movies, Phillips has pushed to make Part II more squalid than Part I. Every scene is riddled with lice and rat droppings; they should hand you an STD kit with your popcorn. The first film offered the fragrant Heather Graham in mitigation, but in Part II, everyone on screen is seen sweating like a rapist, perhaps at the thought of having to put comic lightning back in the bottle a second time. Bangkok looks ugly as sin throughout; Ken Jeong's callback cameo as Mr. Chow begins with the leads fingering his nubbin of a penis, and is abruptly halted by an apparently fatal drug overdose. You long for Paul Giamatti to do something funny with his cameo appearance - to show the Johnny-come-lately leads how it's done - but instead the actor just looks ill, as though he spent much of the shoot on the toilet, and exercises a tedious potty mouth.

As does the film in general. Squalid and funny might have played, but there's a grim desperation about the language here, reminiscent of the recent Paul: Cooper drops the C-bomb in a crowded pancake house, somebody else uses the N-word, which is terribly progressive. Here's an example of how flat this sequel falls: when Nick Cassavetes shows up in the tattooist role that was once earmarked for a certain Mel Gibson, your thoughts drift to how much funnier it would have been to have Mad Mel turn up at this point - and how rich it is that the cast of The Hangover should have taken the moral high ground (in blackballing Gibson), given the general thrust of these films. (Hell, Phillips and co. were perfectly happy to employ convicted rapist Mike Tyson - not once, it turns out, but twice.)

As for the characters the public identified with so the first time around, they've become only more American with time and success: Alan spends a small part of the trip listing obscure fast food chains, while Stu takes the opportunity of a river cruise to trill old Billy Joel songs. Phil and Stu are rude to a Buddhist monk because they can't understand what he's saying; Phillips and his writers only seem truly comfortable inside a titty bar, in part because that's the film's milieu, mostly because it frees their characters to be as loud and as leering as they like. This is self-evidently a boys' town, but it's more of the reductive culture-sacking that marked the second Sex & the City movie, and there's a strong sense that in ditching the Carrie franchise to push this one forward, Warner Bros. have simply come to replace one form of crass cinematic tourism with another. What happened in Vegas should, most definitely, have stayed in Vegas.

The Hangover Part II is on nationwide release.