"What if...?" can be the most painful and frustrating game to play. For me, I often think back on the choice I made when, at 19, I decided to blow the $7000 in my savings account on a backpacking holiday through Mexico, and not on the empty block of land that cost that exact amount in Katoomba, next to my uncle's house and backing a nature reserve and now worth about half-a-million dollars.

It doesn't pay to spend too much time in the land of "what if...?"

New York-based Argentinian director Lucio Castro, makes his feature film debut with End of the Century, about a chance meeting with two men who, it turns out, also met two decades earlier.

For Castro, "what if...?" is an idea that provides fertile ground.

Ocho (Juan Barberini) is a New York-based poet visiting Barcelona, and as the film opens the camera follows him through the city, following his phone to the door of the Airbnb he has booked. On a beach, pretending to read a book, he spots the handsome Javi (Ramon Pujol) in the distance, and again he later spies him walking past his balcony.

Calling out to him, he invites Ravi up for a drink which soon turns into sex. In their post-coital discussion he discovers that the feeling of deja vu or familiarity he feels for Ravi has a reason. The pair have met before, in fact had hooked up two decades earlier, just before the new century rolled in.

Here filmmaker Lucio Castro plays with time, Sliding Doors style, with the pair's first and present time together intercutting. Interestingly, the director deliberately doesn't change the actors' appearances. No different haircuts or clothes or CGI erasure of crow's feet or grey hairs like Scorsese's The Irishman.

In interviews the director explains that this choice is as much about his very restricted shooting budget as it is him playing with the concept of memory, and the way we think of ourselves as how we look in the mirror regardless of the memory we apply that vision of ourselves to.

The way the two men approach their physicality as earlier versions of themselves is fascinating. So lacking in surety.

Castro has a languid approach to time in the film, in terms of his film's pacing. He takes his time, except in a few racy moments, and the exploration of the two men in both time periods, locations, conversations, feels natural, as do the performances from his leads.

He enjoys long silences, which feels appropriate for a lonely traveller.

Castro asks some hard questions for the audience to ponder about those brief moments that could have become real things, real relationships, had we the maturity to allow it for ourselves.

When you look back on a lifetime of relationships, some long-term and meaningful, might one of those one-night-stands of your early years have really been The One? Is it sad to have walked away from it, or it is a joy that it happened at all?

His Barcelona is a lustful experience. I don't mean the sex scenes between Barberini and Pujol, I mean the unrequited and unsated need, longing, to get on a plane again and go somewhere this beautiful. To wander unfamiliar streets and explore. It's a poor substitute to experience it here on screen, and yet it perhaps heightens the experience to know how unattainable it all is at the moment. Almost science fiction.

It is appropriate then that the book Ocho is reading on the beach is Jules Verne's Around the Moon, which is as much about rediscovery as it is about discovery.