According to pseudo-science, us humans only use 20% of our brain’s full potential.

How much different would our existence be if we could tap into the other 80%? Would our newfound higher intellect raise us up to the point where anything becomes possible, or would it slowly rob us of all that makes us human?

Based on the book ‘The Dark Fields’, Limitless succeeds where countless other films have failed by tackling these questions with engrossing, entertaining and highly stylised flair.

Bradley Cooper plays hapless writer Eddy, whose unmotivated and lackluster attitude has left him bereft of inspiration, newly single and saddled with a hangdog appearance so disheveled that former acquaintances mistake him for a tramp.

His fortunes soon change when he runs into his former brother-in-law, who takes pity on Eddy and offers him a way out of his mundane existence – a revolutionary new pharmaceutical called NZT that allows him to tap his full potential. With every synapse crackling, Eddie can recall everything he has ever read, seen or heard, learn any language in a day, comprehend complex equations and beguile anyone he meets—as long as he keeps taking the untested drug.

Soon Eddie takes Wall Street by storm, parlaying a small stake into millions. His accomplishments catch the eye of mega-mogul Carl Van Loon (De Niro), who invites him to help broker the largest merger in corporate history. But they also bring Eddie to the attention of people willing to do anything to get their hands on his stash of NZT. With his life in jeopardy and the drug’s brutal side effects taking their toll, Eddie dodges mysterious stalkers, a vicious gangster and an intense police investigation as he attempts to hang on to his dwindling supply long enough to outwit his enemies.

Limitless is a thriller that has great fun ramping up the conflict and paranoia of its lead character’s predicament while asking some surprisingly philosophical questions – are we still ‘us’ if we become, as the film’s title suggests, limitless? Or is it only when we start using our brains to their full extent that who we truly becomes apparent? And does advanced intelligence make us more or less human?

The film is at its most entertaining when Eddy’s running rings around the rest of us everyday simpletons, be it calling up martial arts moves from an old kung-fu flick to beat off a group of attackers or successfully predicting a car crash to intimidate a business rival. Cooper is so endearingly likeable that it’s hard not to be taken in by Eddy’s knowing smirks and air of overall superiority – in the hands of the wrong actor, the character could easily have come across as an arrogant, selfish prat. Instead he ends up motivating you to go out and better yourself by learning new skills or reading Sun Tzu’s The Art of War.

It’s hardly surprising when it all starts crashing down around him, but the film does a good job of showing Eddy’s confusion and fear as he realises that despite its revolutionary effects, NZT is still a drug like any other, and boy do the withdrawal symptoms bite hard, with one blood-sucking scene showing his desperation with wretch-inducing effectiveness.

There are a couple of solid chase sequences, including an ingenious one that culminates in a slash-happy foray onto an outdoor ice rink, and the time lapse effects when Eddy begins losing track of time are gorgeously trippy, but the film’s loose threads hold it back from becoming the tense thriller it should be. One subplot involving a woman that Eddy may or may not have murdered during a period of sustained memory loss is brought up several times throughout the story before being dropped and never mentioned again. Perhaps the idea was for us to share in Eddy’s confusion, but in a film that ties everything else up so neatly, such loose threads threaten to unravel what is without a doubt a rich tapestry of mind-bending madness.

Still, it’s an exhilarating journey and one that’s sure to leave you wondering just how much more we could achieve if only our brains would let us.

Extras: Director’s Commentary, Alternate Ending, Making Of, and Trailer

Limitless is available on DVD and Blu-ray now.