Love. That intangible, addictive, complicated emotion that is the essence of being human. Now just imagine if it was more straightforward. No more guesswork, no more doubt. What if?

That tantalising prospect is the premise of Fingernails, the second solo film from Greek director Christos Nikou. Probably best known for his collaborations with Yorgos Lanthimos (Dogtooth) and Richard Linklater (Before Midnight), this release is also his first English-language film.

Jessie Buckley plays Anna, who is in a long-term relationship with Ryan (Jeremy Allen White). She should be content: according to a controversial new computer test, the pair are 100% compatible.

But, feeling unsettled, she applies for a job at the Love Institute, which conducts the tests, mentored by instructor Amir (Riz Ahmed). Can a machine really be reliable in affairs of the heart?

Nikou says the idea came to him because of the way people meet and date in the modern world.

“I’m seeing so many people around me using all these dating apps and swiping right or left with their finger. And they’re trying to find the perfect match for them… they’re letting an algorithm decide and suggest people [to them] when I think there is something much more instinctive.”

He says young people in particular appear to be in thrall to online dating.

“All my relationships with girls, especially since I started working in this industry, I met through work,” says the 39-year-old.

“I talked with a lot of younger people that are telling me, ‘Oh, we don’t want to lose time. We’re going to know all the answers. We want to know if we match with this person from the beginning.’

“But for me… you don’t want to know all the answers. And also, it’s the best thing to be surprised. I mean, isn’t it amazing to be surprised by a human?

“For me, love… is chemistry. And the energy is when you see the other person. It’s not a screen.”

It’s hard to pin down when the dystopian drama is set, although it definitely predates modern technology. That was a deliberate choice on the part of Nikou.

“We tried to create something timeless because first of all, love is timeless. And at the same, time we tried to create something… more recent. The last reference in the movie is Notting Hill because Hugh Grant is the only one who knows what love is!” he laughs.

“And we wanted to make a comment on technology. We tried to avoid digital technology in the movie and cell phones because we felt that love [just] goes through cell phones [with dating apps] right now.

“We wanted to… imagine, what if there is only one device that somehow symbolises all technology and everybody goes there to find their own answers about love? When actually, we don’t have to go there, you just need to follow your instinct.”

If you’re wondering how the machine tests compatibility, a warning for the squeamish – look away now.

The couples have to have a fingernail removed, which then goes into the machine.

“We tried to not show a lot… it’s not the body horror some people describe!” Nikou is at pains to point out.

“It’s just an allegory for me, something symbolic. So of course you are feeling a little bit uncomfortable [watching it] but also it’s like love because when you are in love, you’re feeling uncomfortable at the same time.

“The characters are sacrificing something for love, and they’re feeling this pain because we want to equate the pain of love with the pain of losing your nail,” he explains.

“I also wanted to make a comment on technology and… I wanted to take something from the fingers. Cell phones are the extensions of our fingers and the nails are the only part that protects the fingers.”

The couples who attend the Love Institute also undergo various exercises ahead of the fingernail test, to see how well they work together as a pair.

“I’m seeing so many couples, especially in the US, going to couples therapy. And they follow what the couples therapists are telling them and we were trying to make something similar to that,” Nikou says.

One exercise sees one half of each couple blindfolded before they walk around a room, individually sniffing a line of people (all just in their underwear) to see if they can pick out their partner.

Anyone familiar with Nikou’s previous work won’t be surprised to find absurdist comedic elements like this puncturing the tension. Others include daring underwater challenges and skydiving.

“I would want to do the one with the blindfold when you have to smell your partner because I would love to be somewhere with 100 people and to try to find my girlfriend. Isn’t it fascinating that you are living with this person every day and maybe you don’t even remember how this person smells?”

As Anna’s relationship with Ryan begins to fracture, largely thanks to Ryan not putting in much effort to keep things fresh, Anna finds herself drawn to Amir.

Buckley and Ahmed certainly give the film star pulling power, and the on-screen connection between the couple is palpable.

“They’re amazing actors, but mostly they’re amazing humans,” Nikou says.

“So it was very easy to work with them. I love how Jesse surprises me all the time in her performances, and how Riz is a chameleon by adapting to something comedic [and then] to something dramatic.

“They’re both very warm on screen. But we have never seen them both in something really romantic. Jessie has done more dark stuff in the past. I believed they would have this great chemistry and I hope that it works.”

The film has divided the critics, although most agree that the casting is a hit.

Variety’s Guy Lodge described it as “a quietly searching and yearning science-fiction romance”, noting that “Buckley and Ahmed play off each other exquisitely”.

Alissa Wilkinson, from Vox, wrote that the movie was “funny and ultimately heartwrenching… kind and thought-provoking”.

But the Guardian’s Charles Bramesco concluded that “the evasive, guarded acting from the main players can only do so much to elevate the paltry material Nikou gives them to work with”.

And Deadline’s Todd McCarthy concurred: “The passing pleasures of watching the fine young actors… can’t make up for the increasing distaste that develops from contact with Fingernails, an irritating and, finally, ridiculous examination of relationship matchmaking carried far too far.”

Nikou hopes the pair’s performance and his film’s interesting premise will keep viewers thinking after the end credits roll.

“Love is not something that you prove but something that you work on. Yesterday, we had a screening and a girl in her early 20s asked me, ‘Can you give me any advice about love?’ And I said, ‘No, I don’t want that responsibility!’

“She said, ‘All my friends are using these dating apps and I’m trying not to because I don’t feel that it’s right.’”

The film-maker, clearly a romantic at heart, did end up giving her some guidance about relying on algorithms and apps.

“Don’t do it. Follow your instinct. Do what you have here in your heart.”

Fingernails is streaming on Apple TV from 3 November.