In any normal year this might have seemed a pretty decent Venice. But in 2020, the fact that the Venice film festival happened at all seems nothing less than miraculous. Until the last minute, many wondered whether things would go ahead, but they did – and far more than just adequately. The idea of a major film festival happening live seemed almost unimaginable in the time of Covid-19, but while many festivals went strictly online, and Cannes was cancelled altogether, the Venice team managed to attract an audience to the Lido with a varied and impressive slate of films.

True, there were no A-list American movies at an event that has thrived on them of late, notably sparking an international controversy with last year’s winner, Joker. The big studio films weren’t here; neither were the Americans in general, for travel reasons. Asian visitors were also conspicuous by their scarcity. But overall, the absence of Hollywood made this year’s Mostra a film festival of the traditional sort: a taster menu of world cinema at its most diverse. And the best films were a pleasure to watch under well-organised, efficient conditions that made visitors feel safe and relaxed: masks worn in screenings and within the Casino compound, with only alternate seats in use. Press passes were reduced by a third, so that some usually crowded venues felt eerily desolate. But then, it was also easier than ever to get an espresso.

Things kicked off with the first Italian opener in years, at best a justifiable goodwill gesture for local viewers: The Ties, a clunky family melodrama that was mainly a showcase for some top Italian actors, including Laura Morante and Alba Rohrwacher. Things picked up considerably after that, although I didn’t care for most of the Italian fiction here, except for playwright Emma Dante’s adaptation of her own The Macaluso Sisters, an idiosyncratic, exuberant meditation on siblinghood, time and the idea of home.

Bizarrely, the festival’s absolute hot ticket was a half-hour short – Pedro Almodóvar’s The Human Voice, a free adaptation of Jean Cocteau’s play. A solo Tilda Swinton, as a woman on the phone to her neglectful lover, paces a typically lavish Almodóvar set, but this time it’s part of a deserted sound stage – a Brechtian touch with echoes of performance art. Cramming the intensity and meticulous execution of the director’s features into a mere 30 minutes, this was a sumptuous piece and, given how many recent Swinton performances have been oddball support roles, a rare, relishable opportunity to see her giving a full-blown lead, commandingly and with wry grace.

Overall, it was a terrific actors’ festival. In competition, Vanessa Kirby dazzled twice. Once was in Kornél Mundruczó’s Pieces of a Woman, a solemn, vaguely Cassavetes-ish melodrama in which she plays a woman coping with the aftermath of personal tragedy. Then she was in The World to Come, by Norwegian director Mona Fastvold, about a passionate romance between two married women in a 19th-century farming community. Set in a vividly inhospitable landscape, and driven by voiceover with a distinctive literary ring to it, it pairs Kirby with the equally excellent Katherine Waterston. It also had a superbly original woodwind-laden score by British composer Daniel Blumberg.

This beautifully executed work could well be the Golden Lion contender that wins over the jury, led by Cate Blanchett and including actor Matt Dillon and directors Joanna Hogg and Christian Petzold. Another likely candidate is The Disciple, an austere drama from Chaitanya Tamhane. It’s a raga saga – the story of a young Indian classical musician (Aditya Modak, superbly reserved) on a quest for artistic purity and perfection in a world dominated by razzle-dazzle TV talent shows. Contemplatively paced and intensely mature, it’s one of the Venice films I most want to see again. Another competition highlight was the veteran Andrei Konchalovsky’s Dear Comrades!, a steely, black-and-white account of the 1962 Novocherkassk massacre, in which KGB snipers opened fire on demonstrating factory workers. Some critics suspected a veiled pro-Putin statement somewhere in here; this seemed to me an overingenious reading of a passionate and very human drama, with a terrific lead from Julia Vysotskaya.

It was a bumper year for documentaries. The famously indefatigable Frederick Wiseman, now 90, gave us City Hall, a four-and-a-half-hour study of the administration of Boston, delving into every conceivable area (housing, road maintenance, animal welfare, celebrations for the Red Sox), and offering a powerful vision of civic values, with enlightened Democrat mayor Martin Walsh flying the flag for compassion and responsibility in the Trump era. Nathan Grossman’s I Am Greta was a low-key portrait of Greta Thunberg that affectingly got to the person behind the myth.

The devastating Final Account was the last work by the late UK documentarist Luke Holland, who set out to interview the last surviving Nazis, who recall their war; the result is dispassionate, rigorous and predictably chilling. And Gianfranco Rosi’s Notturno (Nocturne) offered an impressionistic vision of the effects of war in several Middle Eastern countries. It’s imagistic, sometimes beautiful and commentary-free, because the pictures speak for themselves, nowhere as starkly as in the children’s drawings of Isis atrocities they have witnessed. It’s another definite Golden Lion contender.

We also saw some some impressive mainstream offerings. Regina King’s theatrical but assured One Night in Miami evoked a 1964 meeting between Malcolm X, Muhammad Ali (then Cassius Clay), sportsman and actor Jim Brown and soul star Sam Cooke, with four terrific performances (especially from Leslie Odom Jr as Cooke). Another early-60s story was Roger Michell’s briskly entertaining The Duke, with an affably superlative Jim Broadbent as an old-school English eccentric, a Durham man tried for stealing a Goya painting.

There was some tense genre-twisting in Roderick MacKay’s The Furnace, an adventure thriller about the Asian camel-drivers who came to Australia in the 19th century, a strong addition to the thriving cycle of outback westerns. And for sheer throwaway comic pleasure, there was Mandibules from French farceur Quentin Dupieux, the story of two idiots and a giant fly; insouciantly outré, it’s perhaps best described as Buñuel’s Bill & Ted’s Excellent Adventure.

My bet for the Golden Lion? Don’t be surprised if it turns out to be the last film that played in competition – the superb Nomadland, by Chloé Zhao, the Chinese director behind 2017’s The Rider. This is another docudrama study of contemporary America, starring Frances McDormand as a woman who loses her Nevada home and joins the multitudes of US nomads searching for a livelihood, a new meaning to life and a new community on the road. David Strathairn co-stars, but the cast is mainly composed of non-professionals effectively playing themselves and bringing their own hard-earned experience to the screen. It’s visually beautiful and extremely tender, with McDormand quietly radiating humanity.

But in terms of sheer originality, toughness and political edge, I’m rooting for a Mexican film that felt like an incendiary device thrown into the selection and that, of all the fiction here, most urgently reflected the stresses and extremities of 2020. Michel Franco’s New Order begins with a society wedding among Mexico’s super-wealthy, plunged into chaos when a working-class revolution erupts. But once the authorities take charge, no one is spared, nor is it clear who the authorities actually are and who really has control.

This is a hugely confrontational film and likely to be controversial: could it be read as an expression of middle-class paranoia or is it a declaration of the inevitability of social change (and not just in Mexico)? Either way, it offers a powerful tableau of a polarised country of haves and have-nots (those who do or don’t have power, rather than just money). It has the dystopian lucidity of JG Ballard and the icy rigour of Michael Haneke. One of the films of 2020, not just of Venice, it reminded us that the world is a frightening place, while this year’s festival made those who could attend very happy to be out and about in that world again.

Jonathan Romney’s picks from Venice

Best feature films New Order (Michel Franco); The World to Come (Mona Fastvold); The Disciple (Chaitanya Tamhane).

Best documentaries Notturno (Gianfranco Rosi); Final Account (Luke Holland); City Hall (Frederick Wiseman).

Best performances Julia Vysotskaya, Dear Comrades!; Katherine Waterston and Vanessa Kirby, The World to Come; Tilda Swinton, The Human Voice; Jim Broadbent, The Duke.

Most full-on performance Andrew Garfield as a deranged YouTube star in Gia Coppola’s strident satire Mainstream. The film is dreadful, but full marks to its star for not just chewing the scenery, but swallowing it whole, regurgitating it and feeding it to the 5,000.

Best crack-up moment Greta Thunberg splitting her sides at a photo of her dad meeting the pope in the documentary I Am Greta.

Best deja vu moment for this critic Willem Dafoe in Abel Ferrara’s documentary Sportin’ Life, reading out my thumbs-down Observer review of Ferrara and Dafoe’s last collaboration, Siberia. Given that it was very negative, a sportin’ gesture indeed.

• The winner of the 2020 Golden Lion was announced after this article was published