There can't be many aspects of the Second World War that have not been subjected to screen scrutiny. But Nicolas Steil has alighted upon the little-known ordeal of the French and Luxemburger `réfractaires' who opted to go into hiding rather than be conscripted for military or civilian service in the Third Reich. Unfortunately, while Undercover War offers some intriguing insights into the pressures of being cooped up in subterranean hideaways for long periods, it suffers from stereotypical characterisation and frequent leaps in narrative logic.

Forced to attend a German university by fascist father Patrick Hastert, Grégoire Léprince-Ringuet returns to Luxembourg after Hastert's assassination in 1944 determined to fight the Axis. But, rather than join the resistance, he is smuggled by a family friend into an abandoned mine, where he becomes part of a community condemned to remain hidden rather than confront the enemy.

Léprince-Ringuet gets off to a bad start with group leader Michel Voïta and hard-nosed Communist Carlo Brandt, who has aspirations to command. Moreover, his reluctant acceptance of his situation is not eased by the presence of his bitter rival Guillaume Gouix, whose occasional nocturnal visits to the nearby town cast suspicion over his loyalties. However, Léprince-Ringuet befriends the ailing Pierre Niney and finds solace in Marianne Basler, who risks the ire of her collaborator husband to bring meagre food supplies to the shaft.

Steil places much emphasis on the inconveniences and indignities of life underground without sunlight or fresh air. But the need to use a bucket toilet and clean plates with sand pale beside the tensions that develop between individuals whose social differences prevent them from forging a united front against a common foe. Yet, while Denis Jutzeler's sombre lighting and Christina Schaffer's oppressive sets reinforce the sense of confinement and ennui, Steil struggles to generate much drama, as the réfractaires seek to kill time by reading, whittling or playing cards. Furthermore, he also over-relies on moments of contrivance to advance the plot, with several characters seeming to exist solely to furnish Léprince-Ringuet with pieces of information that will precipitate the next showdown or afford him the opportunity to demonstrate his patriotism.

The scene shifts to Norway for newcomer Haakon Gundersen's Betrayal, which stars former Aqua singer Lene Nystrøm as a grandmother looking back on her wartime exploits as a double agent in occupied Oslo. Authentically designed by Helge Lohne and Per Trystad and handsomely photographed by Hans Kristian Riise, this is a solid enough recreation of a true story. But it's nowhere near as effective as fellow Norwegians Joachim Rønning and Espen Sandberg's Max Manus or Dane Ole Christian Madsen's Flame and Citroen (both 2008).

It's the summer of 1943 and Nystrøm is working as a chanteuse at Club Havana, an upmarket joint frequented by collaborationist and Wehrmacht bigwigs and owned by Fridtjov Såheim, who also runs a black market racket supplying booze, fags, cement, steel and information to whoever is willing to pay. He is also in cahoots with SS major Götz Otto, who has plans to profiteer from the opening of an aluminium plant that will exploit Soviet slave labour to provide materials for the Luftwaffe.

When not passing secrets to the Gestapo, Nystrøm sleeps with both Otto and Såheim. However, neither is aware that she is also a British spy, whose reports to ex-boyfriend and resistance leader Kåre Conradi are crucial to the planning of an air raid to destroy the Herøya factory before it reaches maximum productivity. But Nystrøm's loyalty matters much less to the nefarious duo than the arrival of Jockel Tschiersch, an accountant from the Reich General Auditor's Office, who has been sent to investigate some shady transactions.

Gundersen is clearly keen to show that Vidkun Quisling wasn't alone in betraying his country during the war. But sneering civil servants poring over paperwork doesn't make for particularly riveting viewing and it's only when Gundersen finally allows the action to spill into the streets for a slickly edited chase sequence that this supposed thriller sheds its torpor. However, by book-ending the tale with Nystrøm relating events to her granddaughter in New York, Gundersen robs it of any real suspense.

Otto and Såheim are suitably shifty as the villains of the piece. But Nystrøm (who is easily upstaged by Julia Schacht as the steadfast secretary) lacks the presence to convince as a daring heroine playing her admirers off each other in the manner of Carice van Houten in Paul Verhoeven's Black Book (2006). Consequently, despite seeking to commemorate forgotten courage, this is doomed to mean well and deliver little.

Coming into the present, we remain in Scandinavia for A Swedish Midsummer Sex Comedy, in which American director Ian McCrudden attempts to follow in the footsteps of the underrated Colin Nutley by viewing misunderstood Swedish mores with a wry outsider's eye. Focusing on the interaction of guests at a house party, this cannot compare to anything similarly envisaged by Ingmar Bergman or Woody Allen. But it's capably played by a practiced ensemble and stunningly photographed by Dan Coplan to capture the glorious light and colour of the Södermanland coast and countryside.

Daniel Gustavsson and Lisa Werlinder have invited their friends to spend the longest day of the year at their idyllic home. However, while Gustavsson has a planned a surprise for lunch, few are in the mood to do much celebrating. Alexander Karim is fussing over pregnant wife Kari Hamfors Wernolf, while wannabe musician Olle Sarri is depressed because girlfriend Annica Bejhed is desperate to conceive, but he has just discovered that he has a low sperm count. Anna Littorin is also feeling low after just splitting with bashful boyfriend Per Wernolf. However, her vulnerability seems to make her fair game for Gustavsson's old college roommate Luke Perry, who jets in from the United States with preconceptions about Swedes gleaned solely from porn movies.

Despite slipping in the odd sauna sequence and an occasional round of musical bedrooms, McCrudden mostly delights in debunking myths about Swedish sexual emancipation. However, he consistently strays more into Peter's Friends (1992) territory than Smiles of a Summer Night (1955) or even A Midsummer Night's Sex Comedy (1982). Consequently, the humour is never as amusing as it might be and the drama always feels a touch forced and flat.

Perry revels in the role of the brash Yank who seems to think he's been invited to indulge himself at a sort of sexual smörgåsbord, while Gustavsson invites both pity and reproach for springing the wedding proposal that tilts the entire sojourn into a downward spiral. But too many characters conform to types like the expectant father, the repressed Christian, the impotent loser and beauty with misgivings about domesticity. Moreover, too many of the situations they find themselves in are overly familiar from numerous reunion pictures. Thus, while this is genial and exuberant, it lacks the originality and insight to match.

The mood changes considerably for The Fish Child. Having impressed with her debut feature XXY (2007), Argentinian director Lucía Puenzo turns to her own novel for her second outing. Dispensing with the source's canine narrator, she also convolutes the structure of the scenario to make this already teasing Chabrolian thriller all the more enigmatic by the addition of an audacious magic realist sequence.

Affluent Buenos Aires teenager Inés Efron is invariably left to her own devices, as her judge father is writing his memoirs, her mother is preparing to run a marathon in France and her addict brother is in and out of rehab. So, she falls in love with the family's 20 year-old maid, Mariela Vitale. Between bouts of sensual lovemaking, they steal from Efron's father (Pep Munne), who is preoccupied with the death threats he keeps receiving, and dream of setting up an idyllic home together on the banks of Lake Ypoa in Vitale's native Paraguay.

However, the plan goes awry when Munne is murdered and Vitale is taken into custody. Desperate to free her lover, Efront travels into Guaraní territory and discovers not only why Vitale was forced to leave home at the age of 13, but also the truth about the local myth that the spirits of lost children are protected by a merboy in the depths of the lake.

Atmospherically photographed on grainy 16mm by Rolo Pulpeiro, this may not always be as elliptically intriguing as Puenzo's twisting screenplay and Hugo Primeiro's dextrous editing would have us believe. The action is packed with exposition and some of the sins committed by the girls' fathers feel contrived to expose the inequities and injustices that blight South American society. However, there is a genuine spark between Efron and Vitale, with the former bringing the same elfin quirkiness she brought to XXY and the delightful Amorosa Soledad (2008), particularly in the aquatic sequence with Jerónimo Perassolo. So, while this may over-prioritise visual flourish over narrative fluency, it has a noirish potency that takes the curse off its occasional telenovelistic excess.

By contrast, Caroline and Éric du Potet resort to structural elaboration to introduce a little extra frisson to their debut feature, In Their Sleep. Co-produced by Frederic Ovcaric, Rodolphe Guglielmi and Teddy Percherancier, who have done much recently to bring a nasty edge to extreme French horror, this has much in common with such succès de scandale as Xavier Gens's Frontier(s) and Julien Maury and Alexandre Bustillo's Inside (both 2007). But, with its surfeit of flashbacking tricksiness, this always feels like a shamelessly manipulative exercise, whose gore quotient has been upped to entice torture porn addicts.

Still mourning the death of the teenage son who was bizarrely impaled on some railings at the remote Alsatian cottage she was renovating, nurse Annie Parillaud is in desperate need of some relief from her chronic insomnia and an outlet for her pent-up emotions. Thus, when she accidentally runs into youthful stranger Arthur Dupont while driving back from a late shift, she has no hesitation in inviting him back to her place to tend his wounds, especially as he insists that he is being pursued by a burglar who would do anything to prevent him from going to the police.

Convinced by the sudden appearance of a car whose driver seems to be on the lookout for someone, Parillaud heads home. But, as she chats to Dupont, it slowly dawns on her that his story may be nothing more than a fabrication and that Thierry Frémont, who is now prowling around her property in the darkness, may well be her best chance of getting out alive.

Despite the Du Potets striving to generate disconcerting suspense by constantly shifting time frames and leaking clues about Parillaud's fragile state and Dupont and Frémont's actual identities, opinions on this remorselessly bleak picture will very much depend on the viewer's reaction to the sight of a terrified young girl being trapped as she attempts to open the front door and then having her throat slashed by a killer who has just dispatched her entire family with a box cutter. There's no denying that this is a shocking sequence, but the siblings might have followed the example of Henri-Georges Clouzot and Claude Chabrol by concentrating more on psychological trauma than physical violence, as the real fascination here lies in Parillaud coming to question the maternal instinct she has longed to re-experience and in her overcoming a medic-cum-mother's inclination to protect and preserve in order to ensure her own survival.

Another mother needs to escape a confined space in Bedevilled, the debut feature by Kim Ki-duk's longtime assistant, Jang Cheol-soo. Supposedly influenced by Alfred Hitchcock's Psycho (1960) and the Coen brothers's No Country for Old Men (2007), this is a slow-burning chiller that makes some rather laboured comparisons between the potential for violence in town and country settings. Nevertheless, it disconcerts considerably before a spate of sickle slayings reduces it to more predictable genre fodder.

Depressed after failing to prevent three thugs from assaulting an old lady and then refusing to testify against them in court, Seoul bank clerk Ji Sung-won loses her temper with another senior citizen and is advised to take a week's vacation by her boss after she berates her colleagues for assisting someone she had ordered off the premises. She decides to return to her home island of Moo-do. But her grandmother chides her for not staying away for another 15 years and only childhood friend Seo Young-hee seems pleased to see her.

Besides finding solace in her beehives, Seo endures a miserable existence, as she is not only forced to work in the fields by the ageing population and treated as a sex object by her male neighbours, but she is also brutalised by husband Park Jeong-hak, who entertains prostitutes in her hearing and constantly threatens to harm their young daughter, Lee Ji-eun-I. Much to Seo's dismay, Ji offers her little support. But, then again, she hardly stands in her way when the grimly cheerful Seo finally snaps and begins exacting her pitiless revenge upon those who had beaten, exploited and raped her.

Seo ably conveys the victim's inexorable drift towards vengeance. But Ji is too impassive in her haughty indifference to anybody's suffering but her own and this lack of nuance extends to the other characters, who exist solely to abuse Seo and push her closer to the edge of madness.

Jang capably uses Jang Gi-tae's contrasting images of the city skyscrapers and the backwater shacks to explores how Ji and Seo each becomes a victim of their environments. But he dwells overlong on Seo's humiliations and this tendency to gratuitousness becomes more ruinous once the massacre begins. Consequently, having started out as a bleak exposé of the malevolent currents simmering beneath South Korean society, this becomes yet another slash fest, with the blood-letting as often being presented as dark comedy as nightmarish horror.