After a tough day in which he receives an eviction notice at home and is made redundant at work, Craig (Healy) stops at a bar before returning to his wife (Fuller). There he runs into slacker pal Vince (Embry), whom he hasn't seen in five years. They also get into a conversation with Colin and Violet (Koechner and Paxton), who celebrate Violet's birthday by daring Craig and Vince to do increasingly dangerous things for cash. Since both men need the money, they play along. But how far are they willing to go?

Every scene pushes things further along a spectrum from harmless fun to disturbing nastiness to full-on horror. Watching it in a crowded cinema, you feel those around you cringe from the screen at different times. Before the end, pretty much everyone will have their hands in front of their face, recoiling at the unthinkable nature of what's happening while also getting a cheap thrill from the darkly absurd humour that underlies everything.

Craig and Embry deliver remarkably realistic performances as friends who have nothing in common anymore, so are easily coaxed from camaraderie to rivalry. Each actor lets us see their character's internal limits, which as things get increasingly squirm-inducing reveals why they react in ways they shouldn't. Meanwhile, Koechner somehow manages to maintain a sunny cheerfulness that unnerves us even further, while Paxton provides an intense presence even with only minimal dialog.

Intriguingly, the director and writers never moralise about the huge themes they throw around. As they pull us deeper into a nightmare of amorality, it's impossible to ignore our own feelings. And as things progress into fairly unimaginable territory, we're shocked both by what we see and how we feel about it. We know this is a black comedy awash in over-the-top irony, and yet our stomachs churn to think about being in the same situation. Which is an impressive feat for any filmmaker.

After the death of her teen daughter Alice (Hollowood in flashbacks), Rebecca (McCormack) moves to Cornwall with her younger daughter Eloise (Richards) and takes a job as vicar in a tiny seaside church. Although her husband (Teale) can't move due to his job. Rebecca also helps out at a community centre run by Daniel (Dimsdale), and it's there that she spots Radka (Stoimenova), a Bulgarian teen who reminds her of Alice. As Rebecca starts helping Radka improve her English, Eloise quietly has her own obsessions.

Essentially this is a story about the different ways people deal with grief, but the filmmakers try so hard to make everything Deep and Meaningful that nothing is. Eloise is exactly like Rebecca, keeping her thoughts and feelings to herself as she sulks and smokes. And Radka's more self-destructive ways brings out Rebecca's damaged maternal instincts. But the ways these characters interact never feels remotely truthful: their encounters are all carefully scripted, as if nothing and no one exists in the world outside this screenplay.

The cast members do what they can with the material. McCormack is compelling at the centre, helping us understand what drives Rebecca even when she does something inconceivable. Richards has real screen presence but is wasted in the role. And Stoimenova struggles to find the centre of a character who changes personality in every scene. Like these three, the other actors merely serve to make a point, so there's never a hint of complexity.

In other words, this script was nowhere near ready to put on screen. It needed a severe reworking to loosen it up and breathe some life around the edges, to make things a bit messier and more emotionally resonant. As is, we can focus on some of the performances and some very nice-looking actors as well as the lovely coastal landscapes. But the plot and dialog leave us cold.

Former comic Mark (McInnes) is dying of cancer, so he's making a video to teach his unborn son how to stand up for himself. His feisty wife Margot (Neuringer) doesn't know any of this, and thinks he's making a documentary with slacker film school grad Bryan (Aiken). But as Mark's project shifts into a mentorship programme to help Bryan learn how to get a woman, he has a meltdown, quits his day job as a TV writer and leads Bryan into experimentation with drugs and sex. Which of course causes big problems with Margot.

It also brings trouble for the film itself, as we find it impossible to sympathise with Mark. He may be smart and funny, but he's also an impulsive, insensitive, fart-obsessed idiot who's turning Bryan into a jerk as well. This takes the film's more interesting element - Mark's impending fatherhood and Bryan's lack of a role-model - and plays it for mere gross-out laughs, broad comedy (a dress-up montage) and dramatic tease.

Because of course the main point is that being a man means taking responsibility for your actions. And it takes both characters several contrived plot twists to realise this. Fortunately, both actors deliver strong, honest performances that hold our attention. Sometimes we even like them. And there are sharp turns from Neuringer, Costanzo (as an ex-addict buddy) and DeFriez (as Bryan's odd flatmate) in supporting roles that feel carefully concocted.

The dialog has a terrific improvisational tone, especially as Mark's patter escalates into full-on stand-up routines that are relentlessly vulgar and infused with that laddish arrogance that characterises so much of American culture. But before the oddly tidy, corny finale, there are telling observations as well, including lessons on how to cope with the tsunami of emotions women bring to the table. And the fact that the secret to humour is brutal honesty with a hint of vulnerability.

Theatre designer Fionnan (O'Conor) is driving his fiancee Ruth (Huberman) crazy by being too-involved in the wedding plans, so she asks his best man Davin (Scott) to plan a stag weekend. Fionnan (pronounced fin-OAN) and Davin dutifully kit themselves out in outdoor gear for an epic camping trip with Fonnan's brother (Legge), his partner (Bennett) and their friend Simon (Gleeson), but things take a turn when the bride's out-of-control brother The Machine (McDonald) joins them. And as they bond, their gentle hiking weekend degenerates into a series of chaotic adventures.

The realistic, sparky characters are well-played by a likeable cast. McDonald has the crazed scene-chewer role, tipping the film far outside believability the moment he walks in. It's actually rather breathtaking how quickly The Machine derails the trip, and the film as well. And all of the other characters do inexplicable things as a result. But there are much more interesting things going on under the surface, which give the actors, especially Scott, some strong scenes to play.

Filmmaker Butler maintains a warm, generous tone, with snappy dialog and witty directorial touches. It's beautifully shot in gorgeous locations, with amusing Irish gags, such as an ongoing debate about the merits of U2. It also knowingly explores the exhausting details of wedding planning, the little things that put us off relationships, the demands of machismo and most importantly the issue of tolerance within families. The lessons learned are a little heavy-handed, but feel earned after all the mayhem.

Of course, The Machine forces these guys to break out of their ordered lives and face feelings and issues they have long neglected to deal with. And they in turn help him break his own problems. So even though this is essentially a wacky romp, it's in the surprisingly serious moments that the film finds the resonance it needs to hold our interest. Because when The Machine is making things messier and messier, we just roll our eyes and wish it would end.