Stanley Kubrick's 2001: A Space Odyssey (1968) is perhaps the most difficult film to write about briefly and meaningfully. Several paragraphs would be required to discuss the `plot' and, even then, one would only be able to scratch the surface of its complexity and subtextuality. A similar amount of space should really be devoted to the far-sighted authenticity of the production design and the ground-breaking nature of the visual effects. And, then, there's the issue of its legacy. Did 2001 confirm the arrival of New Hollywood or did it merely embolden the brats and nerds who would hijack screen science fiction a decade later and usher in the blockbuster era that has paralysed American film-making ever since? Is it a timeless masterpiece or the herald of endless mediocrity?

Adapted from the Arthur C. Clarke story, `The Sentinel', but also clearly influenced by George Pal's Conquest of Space (1955), Kubrick's vision of human interaction with a superior alien force remains the most ambitious and the most exquisitely realised picture ever made in this country. Quite whether it merits John Lennon's contention that it should be screened 24 hours a day in a special temple is another matter. But this four-part voyage from the dawn of time to infinity and beyond continues to spark debate about the content and its meaning, as well as the significance of the black monoliths that are crucial to the action, despite lingering on its periphery. Doubtless, further screeds will be published in print and online to greet a reissue that forms part of the Sci-Fi: Days of Fear and Wonder season at the National Film Theatre in London. But there can never be a definitive interpretation of or verdict on a feature that boldly went where none had gone before without having to venture to a galaxy far, far away.

Mention 2001 to people of a certain age and they will inform you that its use of Richard Strauss's symphonic poem, `Also sprach Zarathustra' prompted the BBC to appropriate it for its coverage of the Apollo moon programme. Kubrick may have also employed Johann Strauss's `The Blue Danube' to accompany the images of the satellites spinning through space. But the raw intensity of the 1896 piece sets the tone for the opening segment, which is set four million years ago on the African savannah of the Pleistocene Age and shows how herbivorous hominids learn how to use animal bones as tools and weapons after touching a mysterious black slab that appears in a crater beside a watering hole.

The shocking transition of the ape-men from peaceful innocents to hunter-warriors is nothing, however, compared to the match shot that sees a bone flung into the air become a Pan Am shuttle transporting William Sylvester to the Clavius lunar base to investigate the `Tycho Magnetic Anomaly One' that had apparently been deliberately buried some four million years earlier. Fielding questions about an epidemic from Soviet scientists Margaret Tyzack and Leonard Rossiter, Sylvester poses for a photograph beside TMA-1 and detects a high-pitched radio signal inside the monolith (which resembles the one seen in the prehistoric sequence).

Eighteen months later, Discovery One heads for Jupiter with three scientists in cryogenic hibernation alongside pilots Keir Dullea and Gary Lockwood, who control the craft with the aid of a HAL 9000 computer (voiced by Douglas Rain), which may be so advanced that it has genuine emotions. When a fault is detected in the main antenna, Hal recommends reinstalling the part to confirm the source of the problem. But Dullea and Lockwood suspect that the computer may have malfunctioned and, during a secret meeting in an EVA pod, they agree to disconnect it if they notice further signs of abnormality.

However, Hal can read the astronauts' lips and it casts Lockwood adrift during a space walk and cuts the oxygen supply to the sleeping crew members when Dullea takes an EVA to retrieve his comrade's body. Denied access to Discovery, Dullea breaks in through the emergency airlock and ignores Hal's pleas not to disable all but his essential programmes. Consequently, the computer regresses to an earlier incarnation and proceeds to sing the song `Daisy Bell' before Dullea finds a video message from Sylvester revealing the discovery of the monolith on the Moon and his bafflement as to why it should be sending radio signals to Jupiter.

On reaching the planet, Dullea sees another monolith in orbit around it. However, as his EVA pod approaches Jupiter, it is caught up in a vortex of dazzling light that whisks him at tremendous speed through colourful and fantastical cosmological phenomena. On coming to rest, a now middle-aged Dullea finds himself in a suite of rooms decorated in the late French baroque style. He sees an older version of himself consuming a last supper of bread and wine before noticing his dying self reaching out towards the monolith at the foot of his bed. This decision to embrace the unknown results in Dullea being reborn as the foetus of a Star Child, which floats through the universe in a transparent orb that affords a spectacular view of the Earth below.

Of the many things worthy of note in this challengingly ambiguous treatise on evolution, extraterrestrial existence and humanity's relationship with seemingly infallible machinery, the standouts have to be the production design of Ernest Archer, Harry Lange and Anthony Masters, the cinematography of Geoffrey Unsworth and the slit-scan special effects of Douglas Trumbull. The intelligent use of silence and music is equally laudable, as is the stylised playing of actors who seem to realise that they are merely props in a grand cinematic design. But what sets this apart from any film of its time and in its genre is Kubrick's trust in the audience to follow and process difficult concepts and his utter refusal to use spectacle solely to amaze and amuse. He sought to inspire awe and fire the imagination in a bid to coerce viewers into contemplating their place in a grand scheme and to speculate about who or what is watching over us with such paternal, but also possibly proprietorial interest. And all this from a man who refused to enter an aircraft after a runway incident while piloting a plane at Teterboro Airport in New Jersey had rendered the once intrepid Stanley Kubrick earthbound.

Kubrick was a keen student of conflict through the ages and would no doubt have admired debutant Paul Katis's use of the desert landscape in Kajaki: The True Story, a reconstruction of a terrifying ordeal endured in Afghanistan on 6 September 2006 by members of the Third Battalion, the Parachute Regiment. Given the insight he provided into life in boot camp in Full Metal Jacket (1987), Kubrick might also have applauded the bantering sense of camaraderie achieved by Katis and screenwriter Tom Williams. But he would also have realised that this has much more in common with Tom Petch's The Patrol (2013) than Kathryn Bigelow's The Hurt Locker (2008). Nevertheless, this is a difficult film to criticise, as it is being self-distributed through Alchemy Releasing, with a sizeable portion of the profits being earmarked for various military-related charities.

When not patrolling the area of Helmand Province around the strategically vital Kajiki dam, the men of 3 Para try to occupy themselves with good-natured taunting, pornography and chess matches played with discarded water bottles. Morale is good under Corporal Mark Wright (David Elliot), but everything changes during a routine patrol on what would become known as `the day of days'.

While scouting the terrain adjoining the dam, sniper Stuart Hale (Benjamin O'Mahony) spots what he believes to be a Taliban roadblock. When he closes in to investigate, however, he steps on a landmine that blows off the lower part of his leg. Desperate to assist their fallen comrade, Wright and medic Paul `Tug' Hartley (Mark Stanley) rush to the spot. However, they have entered an unmarked minefield left behind by the Red Army in the 1980s and Corporal Stuart Pearson (Scott Kyle) also loses a limb when he seeks to help his pals. Realising that they are trapped, Wright contacts the base and requests a helicopter to winch the men to safety. However, the Chinook dispatched lacks the necessary equipment and the downdraft it generates in trying to land causes another explosion that injures Wright and two more of his unit.

Those familiar with the story from the headlines will remember how this tragic incident played out in the scorching sun after the arrival of better equipped American Black Hawk choppers. But Katis and Williams are reluctant to apportion blame in a film that nails its colours to the mast in seeking so scrupulously to avoid referencing the politics of the war. This is understandable, given the support that the project received from the armed forces and the survivors of the calamity. But this embedded approach undeniably enervates a drama already somewhat hidebound by its resolution to be as true to fact as possible.

As with Danis Tanovic's No Man's Land (2001), gallows humour seeps into the exchanges between the brothers in arms, even at the height of the emergency. But Williams barely does more than sketch in the backstory essentials for the key personnel and this deficient characterisation restricts audience identification with the victims and their hapless would-be rescuers. However, cinematographer Chris Goodger wisely eschews the shakicam run`n'gun technique that has become such a cliché in recent combat pictures (or, indeed, the vast majority of supposedly visceral action sequences) and uses the static, widescreen frame to connect the soldiers with their locale and, in the process, to ratchet up the suspense because the viewer never knows where the next detonation might occur.

Coming from a corporate film-making background, Katis demonstrates a decent eye for a telling image and a fine sense of rhythm and realism. He also insists on confronting the audience with graphic evidence of the damage that a landmine can do and Cliff Wallace merits mention for his gruesome make-up effects. But the great strength of this unflinching reconstruction is its emphasis on the ordinariness of both casualties and heroes alike. A couple of the regional accents waver in the heat of the moment, but this serves as a timely reminder of the sacrifice made by those who served in both Afghanistan and the trenches of the Great War, whose centennial spectre casts a grim shadow over this well-intentioned enterprise.

The savagery of warfare is laid bare by documentarist Göran Hugo Olsson in Concerning Violence: Nine Scenes From the Anti-Imperialistic Self-Defence, a harrowing follow-up to The Black Power Mixtape 1967–1975 (2011), which similarly mines the Swedish news archives to offer fresh perspectives on a key moment in history. The focus this time is post-colonial Africa and Olsson structures his footage around extracts from the first chapter of Martinican psychiatrist-cum-philosopher Frantz Fanon's seminal text, The Wretched of the Earth, which he dictated to his French wife, Josie, as he battled the leukemia that would eventually kill him at the age of 36. Fittingly, Olsson presents the text in its spoken and written form, as he fills the screen with key phrases as they are read on the soundtrack by singer and activist Lauryn Hill. Some may consider this a Godardian gimmick, but the text focuses the mind without necessarily distracting from imagery that has lost none of its power to shock and shame.

As the subtitle suggests, this dissertation has been divided into nine segments, with the emphasis falling on those countries previously ruled by the British and the Portuguese. However, Olsson is not against criticising Swedish attitudes to the concept of the White Man's Burden, as he shows Olle Wijkström and Sören Lagergren of the Liberian-American-Swedish Minerals Company enlisting the help of the Liberian army to evict striking miners from their homes and a missionary couple in Tanzania struggling to answer a TV news reporter's questions about why they feel the need to impose Christianity on the locals and why they have prioritised the building of a church over the establishment of a hospital. The white settlers in Rhodesia fare little better, as one supremacist farmer is depicted ranting about the material aspirations of his labourers and his dismissive treatment of one who crosses his path makes it all the more remarkable that the country's passage to becoming Zimbabwe was not much bloodier.

Elsewhere, however, transition came at a greater cost. A vicious war was conducted by the Portuguese and the Popular Movement for the Liberation of Angola and Olsson includes footage from 1977 of the MPLA rebels as they prepare for a dawn raid on the base at Cabinda. He also recalls the deeds of Antonio de Spinola in both Angola and Guinea, while showing clips of the soon-to-be assassinated Amílcar Cabral, whose battle for independence in Guinea-Bissau is summed up by scenes of a wounded soldier being operated on in a rough-and-ready field hospital. His courage chimes in with the Marxist songs being chanted by the women of the Mozambique Liberation Front (FRELIMO). But the single most striking image in the entire film centres on a Guinean mother and baby who each lost a limb while she was breastfeeding during an air raid by the infamous Fiat G.91 planes used by the Portuguese air force.

Each image seems to support Fanon's contention that `colonialism is violence in its natural state and it will only yield when confronted with greater violence'. But, while Cabral sent volunteers to the Soviet Union to become trained war correspondents, the bulk of the footage shown here was filmed by Swedish camera crews. Thus, even though Olsson is clearly championing the anti-imperial cause, the slant cast by the historical perspective can never be entirely eradicated. Thus, there are moments when the images edited by Olsson, Michael Aaglund, Dino Jonsäter and Sophie Vukovic feel a touch too knowingly juxtaposed, while the addition of a lilting jazz score strives a little too hard to suggest a colonial insouciance to the suffering being perpetrated in the name of prejudice, power and profit.

Some critics have noted that Fanon had been dead for several years before the incidents shown here took place and they have questioned whether, in seeking to pay homage, Olsson has actually done him a disservice by presenting him as a weary soothsayer rather than an acute commentator on the oppression and uprisings of his own times. The decision to use Hill as Fanon's also seems a bit calculating. But, while this is necessarily less focused than The Black Power Mixtape, it still provides plenty of food for thought and should send viewers back to bulletins about Iraq, Syria and Afghanistan - as well as the continuing, but often less widely reported conflicts across Africa - with wider open eyes.

Numerous European directors have denounced colonialism over the last half century, but nowhere near as many as those who have taken a tilt at Catholicism. Dietrich Brüggemann and his co-scenarist sister Anna become the latest to join the scathing cadre with Stations of the Cross, a droll satire on blind faith that rather confounds its own scepticism with a miraculous denouement. Divided into 14 parts linked to Christ's progress to Calvary, this is often as stylistically austere as its subject matter, as all but three of the scenes have been photographed from a static camera. But, for all the aptness of the mise-en-scène, this is never as sharp as the central segment of Ulrich Seidl's `Paradise' trilogy.

Somewhere in Germany, Fr Florian Stetter addresses a class for the final time before their confirmation by the bishop. He urges them to become warriors in the army of the Lord by following the teachings of the Catholic Church to the letter and by seeking the devils within their own psyches and driving them away, along with the temptations that entice them into sin. The students listen with a mixture of reverence and indifference. But 14 year-old Lea van Acken is intrigued by both her faith and its interpretation by the Society of St Paul, to which Stetter belongs.

As her classmates file out, Van Acken lingers to ask the priest why a loving God would allow small children to fall sick and she seems only partially satisfied by his answer that an ailment can be a sign that the Almighty has chosen the child for special grace. However, she is impressed by his suggestion that self-sacrifice can bolster prayer and she vows to stop eating and go without warm clothing in the hope that her offering will be pleasing unto the Lord.

The reason for Van Acken's inquiry becomes apparent when she gets home, as her four year-old brother, Linus Fluhr, has yet to speak his first word and his silence only exacerbates the tensions between their parents, Klaus Michael Kamp and Franziska Weisz. The latter is very much the head of the household and blames the emasculated Kamp for their son's condition. But her disdain also keeps Van Acken at a distance and she seeks solace in the unfussy affection of French au pair, Lucie Aron.

She also knows better than to let Weisz know that she has become friendly with Moritz Knapp, a boy from another class who approached her in the library on the pretext of requesting help with his maths homework. He invites her to attend the choir practice at his liberal-minded church, Don Bosco, where they play gospel and soul as well as Bach and hymns. Knowing such satanic sounds would never to tolerated at St Athanasius, Van Acken tells her mother that a girlfriend is keen for her to join the choir. But Weisz refuses to consent to her daughter participating in musical orgies and she so convinces Van Acken that dabbling in such ditties can only inflame the passions that the teenager confesses her failing to Fr Stetter, who is dismayed to learn that she had entertained sexual yearnings for Knapp.

Dismayed at having sinned so wantonly, Van Acken refuses to dance to the pop music played in Birge Schade's gym class and orders Knapp to leave her alone when he tries to take her side. She also brushes aside Aron's concern about her appetite and, for once, is glad that her parents pay so little attention to her, as they fail to detect that she is looking pale and drawn. Indeed, she is so weak that she faints during the confirmation ceremony.

Weisz is more embarrassed than concerned. But, when Van Acken begins having breathing difficulties, she asks Stetter to give her daughter communion and is as stunned as everyone else when she chokes on the wafer and dies and Fluhr utters his first word - his sister's name. Convinced that Van Acken should be beatified for performing a miracle, Weisz splashes out on an ornate coffin. But only Knapp shows any real emotion at the funeral, as he tosses a single rose into the open grave.

Although splendidly played by Van Acken and a fine ensemble, this always feels as it is taking the easiest pot shots rather than discussing thornier topics like faith, fanaticism, devotion and gullibility in a little more depth. Thus, such is the monotonous stridency of Stetter and Weisz's austerity that they feel more like cartoon characters than antagonists in a on Christian morality by such masters of the form as Carl Theodor Dreyer, Robert Bresson and Ingmar Bergman. Van Acken's naiveté also seems a little far fetched for a 21st-century adolescent, even for one so firmly under the maternal thumb. But she holds the picture together with an endearing earnestness and a pathetic vulnerability that makes her demise more worthy of a tear than a snort of derision.

Clearly, zeal should be open for lampoon when taken to such monolithically ludicrous extremes. But, even with a primary target like the Society of Pius X (which was founded by Archbishop Marcel Lefebvre in 1970 and rejected the reforms of the Second Vatican Council), the screenplay hammers home the admonitions with such vehemence that the Brüggemanns themselves run the risk of appearing preachily sanctimonious. The references to the youthful saints of yore, for example, could be handled with more comic finesse, as they are already sufficiently disturbing. However, the ascetic restraint that Brüggemann demonstrates in restricting the movement of Alexander Sass's camera around Klaus-Peter Platten's atmospheric sets (which evoke stern Christian art with amusing subtlety) is altogether more laudable, as is the stark insertion of the captions defining each stage on this mournful Via Crucis.

For a man who treasures his privacy, David Hockney has been the focus of a fair few films. In 1966, he was shown working in his studio in James Scott's short, Love's Presentation, since when he has been the subject of such feature documentaries as Jack Hazan's A Bigger Splash (1973), Philip Haas's A Day on the Grand Canal With the Emperor of China (1988), Billy Pappas's Waiting for Hockney (2008) and Bruno Wollheim's David Hockney: A Bigger Picture (2009). Indeed, the latest profile, Hockney, marks the second time that the artist has collaborated with director Randall Wright, as they also teamed on the BBC offering, David Hockney: Secret Knowledge (2003), which explored the connection between the optical devices used by the Old Masters and the digital formats that are impacting upon art today. Yet, while the aforementioned have explored various facets of Hockney's life and work, this intimate study gets closer to the man behind the canvas than ever before.

Seventy-seven at the time of filming, Hockney is clearly in reflective mood, as he opens up both his diaries and his photographic and home-movie archives to Wright and his nimble editor, Paul Binns. What results is an audiovisual montage that owes as much to one of Jonas Mekas's ruminations as one of Hockney's own collages. However, the early emphasis is on a Bradford childhood in the 1940s that is recalled with nostalgic fondness by his sister Margaret and old friends Arthur Lambert and Colin Self. Having left the local grammar school, Hockney studied at Bradford College of Art before moving down to London to enrol at the Royal College of Art.

In 1960, Hockney had his work included in the influential Young Contemporaries exhibition. But he made his name in Los Angeles in the middle of decade, where he discovered the rich colours produced by acrylic paints and produced such seminal works as `A Bigger Splash' (1967), which was hailed as a pop art masterpiece and became one of many paintings to use swimming pools to explore the tensions between surface, space, light and colour. In the same section, Wright also considers such pieces as `Peter Getting out of Nick’s Pool' (1967) and `Autumn Pool' (1978) and the techniques involved in capturing still and moving water, as well as reflections and sky.

Hockney freely admits that he spent much of his youth escaping into the dream world created by Hollywood, but there is nothing overtly Tinseltowny about the works he completed during this period, as he frequently painted friends in everyday domestic situations and Wayne Sleep and George Lawson (whom he painted in 1972) and Celia Birtwell (who graced such iconic images as `Mr and Mrs Clark and Percy', 1971 and `Celia With Green Hat', 1984) readily testify to the relaxed nature of their sittings.

Gallery owners David Oxtoby and John Kasmin, curator Charlie Schieps, artist Ed Ruscha, architects Tchaik Chassay and Philip Steadman and friends and subjects Mark Berger, Don Barchardy, Kenneth Tyler, Jack Larson, Raymond Foye, Melissa North and Joe Clark similarly enthuse about Hockney and his legacy. But the most telling insights come from the man himself, as he provides useful insights into his influences and a detailed analysis of his methodology. Moreover, he speaks with moving openness about his sexuality, his often story relationship with muse Peter Schlesinger and the AIDS epidemic of the 1980s that saw him lose so many close friends and colleagues.

But this is anything but a valedictory tribute, as Hockney remains prolific and he ends his interview by looking forward to a future filled with new ideas. Sadly, some of Wright's ploys to gussy up his portrait misfire, most notably the sans-serif bon mots periodically slapped on to the screen and the recurring use of Nat King Cole's `L.O.V.E.' But the decision to film Birtwell and others in the locations where Hockney painted them is inspired, as is the travelling shot through the Malibu garden that is obviously a cherished haven. Indeed, Wright judges the mood and pace of this celebration with considerable finesse and few would complain if he completed a Hockney triptych in a decade's time.